And that whole "the liberals always ally with the fascists!" thing? Straight up Soviet propaganda. See the thing about the ideologies derived from Marx's writings is that Marx had a deterministic and very simplified view of history that allowed him to make predictions about how the future would play out. And the ideologies based on his writings, take his analysis of history and his predictions as truth, and see the truth of his views, and their own ideology, as confirmed or refuted by those prediction's coming true or failing to. but actually, when his predictions don't come to pass, because he did not actually have a crystal ball, instead of really seeing their ideologies as refuted, they come up with reasons why the prediction was right, and the works just got gummed up for some reason.
And one of those times was that according to the Soviet reading of Marx, the Weinmar Republic was supposed to have a glorious Communist revolution at exactly the moment it instead fell to the Nazis.
So Soviet academics after World War II came up with the justification that the German liberals used fascism to stop the revolution and therefore betrayed the revolution, and underneath their fake liberalism, they're really just fascists, and all they really care about is capitalistic greed and keeping the proletariat down. This had the lovely side effect of being very useful to paint the US led Cold War "free world" as all secretly fascist and just like Hitler.
The tragic irony is that the exact opposite happened from what the Soviet academics claimed. In the years leading up to the rise of the Nazis, the Marxist political associations had splintered into two groups, a liberal wing that was pro-democracy and sought electoral success in the new Weinmar government, and a wing that was still holding out for a glorious Communist revolution that would sweep all aside, and leave them in power. This split was deeply acrimonious, and the more radical wing especially saw the pro-liberal democracy wing as traitors and sellouts. They felt even angrier when that pro-liberal democracy wing actually did achieve quite a bit of electoral success. The revolutionary wing did not achieve electoral success, but they did have street gangs and a sense of grievance and moral purity, so who were the real winners?
But then came the depression and the resurgent Right, and a rise in street violence, and the pro-democracy faction found themselves alone, trying to hold the state together. And when pro-democracy politicians reached out to the Communists, the Communists laughed at them and refused to help. They didn't care about democracy, or preserving it, and these right wing movements, especially the Nazis, looked a lot like the proletarian revolution they were waiting for. So almost all of the communists either stood back or outright allied themselves with the Nazis, and even joined the party, in the hopes that they would guide this revolutionary movement into being the proper Communist revolution they were certain it would become.
And then once Hitler was firmly in power, he purged them from the ranks and had them arrested and/or killed, along with the liberals who tried to warn them.
And it's happening again. The same people who kept insisting that "scratch a liberal, find a fascist," and "the liberals always side with the fascists to betray the revolution", are cheerfully sitting back as the liberals try to hold a democratic government together, and falling all over themselves to welcome our new fascist overlords.