Remember, the social Democrats sided with the Nazis over the socialists. They’ve done it every time they’ve been given the opportunity, and will continue to do so as many times as people fall for their shtick.
“The master's tools will never dismantle the master's house."
-Audre Lorde
You can live in a made up reality that uses lies and half truths to justify regimes. It's really annoying and disgusting, but it's not the biggest problem right now. What is even less tolerable is you using those strategies to divide the resistance to fascism for the purpose of growing your tankie movement. Not all people on the liberal spectrum will side with fascism. Many side with leftists over fascists throughout history. If anything, Stalin trying to take part of Poland, only siding against the Nazis after getting stabbed in the back, shows just how hollow your arguments in favor of MLs and against social democrats are.
I can provide documents from both western and eastern sources that verify what I said about China. Harvard University itself found well over 90% approval by the people of the Chinese government. If we want to talk about appeasement, we can talk about how the USSR tried to form a three way defense pact over Poland with Britain and France, but instead the western nations refused. It was only after that that they signed a non-aggression pact, and that pact only lasted long enough for them to build up their industry to prepare for the inevitable invasion by the Nazis. You can read the letters between Stalin, Churchill, Roosevelt, and Hitler, they’re available online. You can see how western leaders preferred appeasement to defense. You can see how many western leaders not only didn’t dislike the Nazis or Mussolinis fascists, but admired them for their privatization and suppression of working class movements. If Hitler would have kept his genocide to Germany, the west would never have cared. They really didn’t even care about it during either, as evidenced by the wests refusal to take Jewish refugees, a large majority of which were taken in by the Soviet Union.