The party that is currently called the Republican party, which was originally called the Democrat party when Lincoln went from Whig to Republican, has always ostensibly been run by fascists. The original Democrat party that became the modern day Republicans was started around Civil War times, and was mostly all southern states wanting to keep slavery, and owning/subjugating people. The party is literally rooted in evil, sold as "state's rights" - they've been lying about their narrative since the beginning. It's confounding really, because state's rights sound like freedom, but they really don't mean true freedom, they just mean, "we want freedom to subjugate." It's like how North Korea is called "Democratic People's Republic of Korea" - any time something sounds extra freedomey? It generally is the exact opposite.

Throughout history, the party now known as Republicans has always been pro-rich, anti-social-welfare. In the early 1900s, when income taxes began, they voted against income taxes being public information because the rich were crying about their tax return information being public and showing up in newspapers. They also pioneered the concept of poor whites in the south hating Blacks, and dangled a carrot that the poor whites were not only superior to the Blacks, but also that they had a chance of becoming a rich white some day. This made the lower classes infight rather than realize the rich whites were the source of all their woes.

The actual individual citizens that vote Republican, aren't necessarily in this same evil mindset, though. The ideals the party espouses about being fiscally conservative, small government, and such, are often what drive people in the US to vote Republican. There are those that don't think the US government should be responsible for every aspect of supporting the lives of the citizens. Like everything, there is always some validity in viewpoints, but when you mux politics into two binary parties for an entire nation, it makes choosing your politician of choice boil down to whatever you think your biggest issue is, possibly voting for Evil in the process.

Unfortunately, the Republican Fascists in power have wrote a narrative to blind their constituents, and with all the cuts to the US education system over the last decades, the people as a whole are getting dumber, and are more likely to fall victim to the silver-tongued lies.

Because their agenda is very unpopular.

It threatens their power.