“Even Nazis deserve the right to free speech” thing
I'm sure he would say this. But in this specific case it's more of a question of not having any topic be off limits. I know there's a lot of emotions towards the holocaust and anyone who questions it is immediately labeled some sort of neo-nazi (and 90% of the time, that's what they are). Chomsky firmly believes in the Holocaust, because like you said, he experienced it. He's a Jew in his 90s.
But consider a world where you canno make an academic or scientific inquiry into a topic because "the issue has been resolved". What kind of world is that? He was defending a researcher who did an analysis into the Holocaust and came up with significantly different figures. Basically claiming the death toll was inflated. Which is, to the best of the research I've read, entirely incorrect. Something like 6 million people died in the Holocaust and there is plenty of evidence to show that.
But again, the point isn't whether the researcher was wrong or right. It's just that we can't set the precedent that certain topics are "finished" and can't be modified anymore. Because at that point we're not doing science or research - we're falling victim to ideology. Keep in mind the guy he was defending was getting charged with a crime since this was Europe and they have certain laws about Holocaust denial.
So we bring it back to the Lemmy devs. The article I read (I didn't read them all) was an analysis of the death toll of the Mao period and claims the figures were inflated. Does someone posting a link to this or otherwise sharing it make them a "genocide denier" and a "CCP tankie"?
This immediate lashing out when experiencing "wrongthink" is something I think is so toxic and dangerous to having serious discussions about sensitive topics. The more you study these things, the more you realize things are never black and white. There aren't good guys and there aren't bad guys. Or rather, maybe everyone's a bad guy. But I think you get my point.