Growing up in a "non-denominational", independent fundamental Baptist house I was always taught that Catholics weren't Christians because they worship idols. Now that I've left the faith I would easily classify them as being Christian.

While I think many people actually do classify them as Christians they do have some significant differences in their beliefs and practices than most Protestant denominations; and being themselves the largest Christian denomination by far it can be useful in some analysis to treat them as a distinct entity (the answer to "percentage of global population that subscribe to a particular religion" is much more interesting when broken into "Christian Catholic: %" and "Christian Other: %").

There's plenty of great commentary here about why Christianity is divided up into different sects, but I think you're primarily interested in the narcissism of small differences. (https://en.m.wikipedia.org/wiki/Narcissism_of_small_differences)

Basically, if you've read about Dr. Suess' Starbellied Sneeches, you get the idea. Human brains are exceptional pattern recognition machines, and when a society is so homogenously Christian then those small differences become the cleavages along which identities form. That leads to things like Catholic / Christian divisions and the formation of the best joke in The Guardian history:

Once I saw this guy on a bridge about to jump. I said, "Don't do it!" He said, "Nobody loves me." I said, "God loves you. Do you believe in God?"

He said, "Yes." I said, "Are you a Christian or a Jew?" He said, "A Christian." I said, "Me, too! Protestant or Catholic?" He said, "Protestant." I said, "Me, too! What franchise?" He said, "Baptist." I said, "Me, too! Northern Baptist or Southern Baptist?" He said, "Northern Baptist." I said, "Me, too! Northern Conservative Baptist or Northern Liberal Baptist?"

He said, "Northern Conservative Baptist." I said, "Me, too! Northern Conservative Baptist Great Lakes Region, or Northern Conservative Baptist Eastern Region?" He said, "Northern Conservative Baptist Great Lakes Region." I said, "Me, too!"

Northern Conservative†Baptist Great Lakes Region Council of 1879, or Northern Conservative Baptist Great Lakes Region Council of 1912?" He said, "Northern Conservative Baptist Great Lakes Region Council of 1912." I said, "Die, heretic!" And I pushed him over.

https://www.theguardian.com/stage/2005/sep/29/comedy.religion

If you are curious look up the Protestant Reformation, Martin Luther and his 99 Theses.

I'm paraphrasing and my thoughts on what I experienced this but it came down more to the idea that Catholics worship the pope and the saints more than god and jesus. If you were the leader of a nation that called themselves Catholic you could find the Pope telling you what to do when it came to war and if you declared war on another Catholic country the Pope could tell you to stop or to declare peace. To not do so was in danger of having all other Catholic nations declare war.

Not to mention the many saints you are required to pray to, Purgatory and praying for the dead, all of the rituals, services in Latin, worship of the virgin mother, the schism that split the church between two Popes who excommunicated each other, etc.

Protestantism did away with all of that. No single leader, the ability to create different sects that didn't make you an apostate of the church, etc. Now don't get me wrong even the same sect don't always believe the exact same things and it can get pretty nit-picky, but Protestantisn can change with the times more easily than Catholicism can.

The goal was to make less of a ritual cult like Catholicism had become, and more of a focus on the meaning of the the actions of jesus, being able to actually get to heaven without all of the pomp and circumstance that really meant nothing, and all that crap.

The worry is the President would be more loyal to the other Catholics than the rest of the nation and would be bound by cult rules than the will of the people.

Ironically enough right now it's the Catholic President trying to stop rights from being taken away while there are both Protestants and Catholics in the Supreme Court and other facets of the government that are working so hard to do the opposite.

It’s because Protestantism is the dominant form of Christianity in cultures where this language convention exists, and it is a deliberate tactic to other Catholics by labeling them non-Christian. Especially in previous times, Catholics were subject to large amounts of discrimination and antagonism by Protestants, and we’re still dealing with the remnants of this ideology today. I think the only reason it has subsided is the rise of secularism and other more foreign religions that are seen as a greater threat by Christians, forcing them into an uneasy alliance with their former enemies. But remember that tons of Christians used to murder each other over which sect they belonged to.

Interestingly, in Central America, the opposite convention exists, where you are either “Cristiano”, meaning Catholic, or “Evangelico”, meaning Protestant (usually Pentecostal). This is because the dominant group is reversed in that society.

Personally, I view Christianity, Islam, and Judaism as three branches of one religion since they are clearly very similar. But that is the view of an outsider.

some sort of remnant of evangelical puritan protestant ideology?

Yes. It's weird.

Because some sects of Christianity (mostly Southern Baptist) are fucking insane and spiteful.

I can maybe understand it if they're talking about UUs. Speaking as one, we're not entirely sure what the hell we are either. We're in committee trying to figure that out. </self_deprecating_joke>

Hundreds of years of infighting

This might be a regional thing. At least in Germany, where the reformation took place, the term Christian include all groups, protestans, catholics, orthodox etc.

As an ex catholic who grew up near Protestant land, it’s because they don’t think of Catholics as Christians. Some think of them as more like Mormons, others more like Satanists. The plus side is that it was a great card to pull to these people when they proselytized. They’ll tell Protestants they need a better version of jesus, but Catholics scare them.

Catholics see themselves as the root form of Christianity that other versions forked from. Whilst it's not technically true, as there are many versions of Christianity that pre-date Catholicism, in most countries where the term "Catholics and Christians" is used, it's accurate enough

As an American who was raised Lutheran, who was taught a bunch of Romance-Euro-centric world history in school, I always considered Roman Catholic to be the "default" flavor of Christianity. Protestantism in all of its forms are hard forks. It's in the name, even--the Roman Catholic church is what Protestants are "protesting".

To unironically "-and Zoidberg" Catholicism out of Christianity while leaving Protestant flavors included feels completely backwards. I've never heard anyone do it.

But if I did, I could only assume it was due to some No True Scotsman bullshit. "Only we practice the correct way. Everyone else isn't just interpreting it differently, but interpreting it wrong." Sounds like an Evangelical line of thought to me.

They have the next outgroup to eliminate lined up in case they run out of minorities to discriminate against.

Catholics are Christians, but Christians are not necessarily Catholic. For example, Orthodox Christians are not Catholic. Being Catholic requires, at the bare minimum, agreement with the Holy See and implicitly the dogma he endorses. Even this "minor" difference can be used to find non-Catholic Christians.

Precisely, Catholic ⊊ Christian.

The reason why this is the case has to do with the history of Christianity, specifically the various schisms throughout the ages as the Christian faith evolved. That's an incredibly complicated topic which I'm not qualified to discuss.

If you believe your religion is the only correct one, you'll make sure to distance yourself from other variants even of the same faith.

America is far from Europe and if there are people believing the US is the pinnacle of creation and Trump reincarnated Jesus himself, that phrase will eventually come up and stick

Jesse, WTF are you talking about

I've never heard the phrase Catholic and Christians before. Catholic vs Protestant maybe.

Cocaine and crack are different, technically, but they come from the same shit.

I've never heard someone say this.

because historically lumping protestants and catholics together has not ended well.

Discrimination and division are like 99% of what religion is about.

I was raised evangelical protestant in the USA, at some point attending both Seventh-day Adventist and Pentacostal churches. My mother did not consider my Catholic grandparents to be Christians, based on her belief that one cannot be saved by confession/prayer to a saint or clergy instead of directly to Christ. As many other have said, this is not the mainstream definition.

Catholics do a bunch of stuff other Christians think makes them not Christina.

The biggest one is the pope, catholic lore says the pope is the literal spokesperson for God on earth all other religions he doesn't have authority.

Idolatry: other Christian religions don't have a lot of images of saints or anybody other than christ and basically think catholics are wrong for worshipping Mary and saints on the same level as Jesus. Similarly it's the difference between catholic crucifixes (has the dead guy on them) vs regular crosses

Transubstantiation: according to catholic lore when the alter boy rings the bell that is LITERALLY the body and blood of christ you're eating. Pretty sure other religions think this is a step too far.

Because America is built by non-catholic faiths composed of heretics that love to burn women alive, abusers that craft abusive personality cults in hills-have-eyes country, false prophet grifters who tell you god's gonna cure your terminal ilness if you help them get a private jet for their dogs, the hate-worshiping demons that blight the south 'evangelicals' that drive modern american politics, and misogynistic polytheistic pagans wearing the Christian mask while dressed in their weird underwear and tell you you're not allowed to drink coffee but monster energy drinks are a-okay, who all want to be acknowledged as the real Christian faith instead of being labeled as schismatic protestants and chose to go with the common moniker "catholics & christians" instead of "catholics and protestants"

You won’t find me using this dichotomy—I just use the blanket term “Assholes.”

Because religion is all about dividing people into arbitrary groups. Catholicism is a specific type of dogmatic Christian theology

I have never heard anyone say that. Presumably they say it because they don’t know any better.

The same can be asked about the Mormons. It’s Christians who have a weird obsession with deciding who gets to be Christian.

For me, if they believe in the divinity of Christ, they’re Christian.

We're talking about "orthodoxy" here. Wikipedia

In Christianity, one of the first creeds established was the Trinity; God is the one God in three persons: Father, Son, and Holy Spirit. How that works is a mystery unlike anything existing, although we try to illustrate and make parallels.

This is a sharp dividing line for calling anything "Christianity."

Muslims honor Jesus as a prophet, but that does not make them christian, because they deny his deity. Mormons do not believe in only one god (ultimately), or in the Trinity as one, but instead separate see this link.

Both Catholics and Protestants believe in a true Trinity.

As a Protestant Christian, it doesn't make any sense. I think it is just idiotic evangelical puritans being idiotic evangelical puritans.

However it is worth mentioning Catholics and Orthodox people don't allow each other or Protestants to take communion. (Catholics might allow Orthodox but maybe orthodoxy forbids their own members, I don't know that one)

Every US president has been Christian but only one has been Catholic. It is considered as a clear distinction in the US imo

Because the Anglosphere was so xenophobic that even the Irish and Italians were too culturally exotic to them and thus demonized their entire belief system.

Schism was the very first thing the Christian church learned to do.