Antifa USA 2020 is not the paramilitary wing of a german stalinist party, even if "Antifa in Germany 1931" was one. It is not the same organisation. It is a lifestyle branding sold to left wing youth, like Che Guevara t-shirts.
Now there is an organisation in the USA that has recently started to use the Antifa Branding. It's called Torch Network or https://en.wikipedia.org/wiki/Anti-Racist_Action but that one, too is not related to Germany 1931 or to Stalinism.
It might be news to you, but very few of the people who participated in the successful Russian communist revolution of 1917 were knowledgeable about the finer points of Marxism too. You don't really need that many. The rest can be useful idiots. The few knowledgeable people behind the scenes know and exploit this. 6 months before it happened, BTW, Lenin said in a lecture in Zurich that a revolution would not happen in his lifetime. But a rail car full of German cash helped things along quite nicely. So if you think this can't happen here, you should probably reconsider.
Same with Cultural Revolution in China or Khmer Rouge. Same with Nazi Germany - I seriously doubt Hans Sixpack hated Jews or Slavs all that much. In a way, Fascism was too "lifestyle branding". Germans, down and out after WW1, were sold this grand vision of Third Reich and Lebensraum stretching shore to shore on the Eurasian continent. Oh, and if you're against it, not only you'd get "canceled", you'd get shot by the nearest ditch. We're a few years out from that at the moment. In terms of tangibles outside lifestyle branding, BTW, Antifa at the time wasn't that different from fascists themselves. They wanted a communist authoritarianism, hammer and sickle and everything, while fascists wanted more of a capitalist version. Any sort of "democracy" wasn't even up for discussion.
Same with communism. Why wouldn't a "working class" Ivan Sixpack want to "own" the factory he works in? It did not occur to Ivan to think about what that'd actually mean in practice. 5 years later Ivan dies of starvation, 15 years later his extended family ends up dying in Gulag, for being "counterrevolutionary element". He did not end up improving his condition before he kicked the bucket either: the factory is now owned by the state, and it's illegal to not work there. Ivan was a useful idiot, and he outlived his usefulness. Don't be like Ivan.
You add nothing to your claim that it is the same organization and i will keep refuting that as the nonsense it is.
> The FBI says antifa uses social media to organize, but there’s no specific organization or leadership structure.
To me it looks like a very loose group of "anti-parental-authority" youth on the left fringe, which mostly idiolises fantasy-feelgood-anarchism, mixed with some older anti-klan streams that are special to the USA. You can't just claim that is the continuation of the paramilitary wing of KPD 1931 halfway across the planet, then also claim it is basically Thälmanns KPD, which is basically Stalin himself, because all things loosely related are the same thing. I call bullshit.
Those far fetched stories about how revolutionaries have found themselves abused by some autocratic authoritarian putschists are nice and true, but they do not give any substance to your claim that current Antifa USA is a stalinist organization. Your argument seems to be "all leftist revolution must end in stalinism, therefor they are all stalinists", which is so ridiculous, there should be some Godwins law variant for that.
That democracy you speak of is based on the believe in pluralism, yet you deny the existence of pluralism in the vague field that spans from KPD and Antifa 1931 to todays USA. You somehow completely ignore the 1980s hardcore anarchistic punk scene, 90 years of history, and instead you throw in some "cancel culture" and "maoist culture revolution". You have nothing backing your claim that it is a stalinist organization except matching symbols on anti-capitalist merchandise sold for $5.99 and a generalized red scare.
Now i agree with you on warning about the dangers of totalitarian authoritarianism. On that part we are fine. But you are crying wolves because of a freaking chihuahua! Yes that thing is related to wolves, and it is annoying, but you are the idiot for thinking they are the same. Freedom and Liberalism are not attacked by some rioting teenagers in downtown Seattle. Those who make encryption illegal and want everything on the net monitored by the Ministry for State Security for signs of domestic terrorism, those are the wolves.
Now there is an organisation in the USA that has recently started to use the Antifa Branding. It's called Torch Network or https://en.wikipedia.org/wiki/Anti-Racist_Action but that one, too is not related to Germany 1931 or to Stalinism.