Hmm, let's break it down:

a political philosophy, movement, or regime (such as that of the Fascisti)

Could be leftists, conservatives, or any other political group.

that exalts nation and often race above the individual

Well that excludes conservatives, because conservatism celebrates rugged individualism.

Leftism, by contrast, embraces groups above individualism. This is what conservatives usually refer to as neo-Marxism. It's also known as identity politics. It's this idea that we're all members of a group, and that group gives us our identity. Then with intersectionality, you have multiple groups defining identity.

Two caveats:

1. Christians are the exception to the rule, where many conservatives do embrace an identity that can be defined as a group.
2. Leftists do exalt groups above the individual, but those groups are not normally the nation (at least not in the US).

and that stands for a centralized autocratic government

Yes, in general, conservatives support small government, while leftists prefer government regulations over private business, government handouts for the poor, government taxation of the wealthy, and government control of every little thing in life — basically big government.

Centralized? In the US, centralized means federal control whereas decentralized means State and local control. Leftists generally prefer the former, whereas conservatives generally prefer the latter.

headed by a dictatorial leader

Not applicable in the US, but I wouldn't put it past the Left in the near future.

severe economic and social regimentation,

Yep, see this thread for instance. Leftist love regimented control over what we're allowed to think, and they love silencing the opposition.

and forcible suppression of opposition

Oh, you mean like when Biden has his primary opponent, Trump, tied up in court with accusations and a threat of imprisonment? Or, you mean like this very thread where leftists are trying to silence the TERFs? Yes, leftists absolutely love the forcible suppression of their opposition.

In conclusion, no, it's not a perfect fit for leftists, but it's loosely close — and it certainly doesn't fit conservatives even slightly.

Should I be surprised that someone so radically far-left, so as to believe the US has no left, is someone who freely dishes out insults?

No, political agitator, I'm not going anywhere. Welcome to the internet, where sometimes people disagree with you.

It's absolutely true. Look at the DNC policy from 20+ years ago, and you'd think it looks like RNC policy of today. Moving leftward is part and parcel of the notion of "Progressive" politics — moving progressively leftward.

Oh yeah? Educate me, wise old political agitator.

Hmm, sounds like you missed my entire point. Nobody objects to any people existing. Some people object to particular behaviors.

I don't condone murder under any circumstances. But using 56 murders as an excuse to silence anyone online is a disgrace to the principle of free speech.

That misunderstanding is why echo chambers grow. Your fear of being perceived as a Nazi only reveals that you're overly concerned what other people think of you, which strongly suggests that you're young and naive. As you grow up, you'll stop caring what others think of you (hopefully you will — no everyone does), and you'll learn to respectfully engage in conversation with people of divergent viewpoints (even if they happen to believe their personal level of melanin justifies their superiority complex).

What kind of absurd hyperbole is that? Nobody has called for murder. And certainly nobody has committed a murder based on a call for it.

Have you never heard "sticks and stones may break my bones, but names can never hurt me"? It's preschool 101. Speech is never an act of violence.

Additionally, nobody is debating anyone's right to exist.

It's not at all ludicrous to conceive that I may be wrong on any topic. I enjoy learning something new when I'm disproven. It's not easy to convince me (or anyone else for that matter) that I'm wrong, but I'm generally open to the possibility.

It can be a hassle. I run m/FoxNews for news about foxes. The microblog is constantly getting spammed by posts having the #FoxNews tag, which as you might guess is never news about foxes. There's no apparent way to disable the feature where magazines automatically get all content with a matching tag. Additionally, there are no notifications when somebody posts to your magazine, so you need to remember to check it regularly.