I'm a little late on this thread/issue, but I agree with @sabreW4K3@lazysoci.al .
I'm also inclined to push back on the anti-lemmy.ml stance being pushed here. And to be clear, While I'm on lemmy.ml, I joined before "the migration" when it made sense to join the "main" instance as it then was and I have no particular affiliation with them or their politics.
Inline with what sabre is saying, I think there's a certain degree of political entitlement and "defederation-fever" creeping into this general sentiment. I think the communists/tankies should be allowed to do their thing without it being an issue, just like any other niche interest/viewpoint that can build a space here.
I suspect there's some dangerously presumptive politics at play here ... where moderation action is presumed to be "power tripping" mainly because the moderator's politics is presumed to be completely wrong. How about, "yea, that's their thing, it's unlikely something productive will come out of speaking flatly critically about china on lemmy.ml ... their moderation can go overboard sometimes, but their defensive about all of that ... if you want to do that, you'll need to go to a more western instance/community"
Building different spaces with different rules, vibes and beliefs, while simultaneously committing to inter-connectivity as much as possible ... is basically the idea of the fediverse. It allows us to talk to each other without being stuck in one group's (or corporation's) policies and world-view ... and more idealistically, allows us to see different world-views more clearly as we contrast the different spaces we can be connected to. If everything were on lemmy.world, it'd be hard to see the world-view (ha) that the mods/admins and even majority there impose on the rest.
That's the idealism, and I think it's very real.
But the pointy end of the stick is disagreements which lead to downvotes and moderation. That's what enables the creation of a particular space, and needs to just kinda be accepted a bit more.
That's the part not stated enough IMO ... at some point, if you're going to be committed to the inter-connectivity part, you need to be respectful of the fact that another space exists and can be antagonistic to some of your views. That's fine. On reddit, we'd just steer clear of a particular sub-reddit and maybe disparage them elsewhere. De-federation or targeting an instance as plain bad or wrong is a useful tool that the fediverse provides but which, IME, can easily become over zealously embraced in a sort of dog-pile behaviour. A more useful behaviour, IMO, is to try to work out ways that the fediverse can persist with such antagonism and disagreements.
Not being surprised that communists are hard on criticism of communist countries seems like a start to me (where, TBF, such criticism is pretty wide spread in the west to the point that I don't blame them for being cranky about it). Being open to the idea that you can get along with same communists on just about any other issue is a good next step. It'd be the same with criticising tech workers on programming.dev or trans/gender/queer issues on blahaj.zone or criticising western imperialism and capitalism on lemmy.world. Though I suspect the lemmy.ml admins could do a better job at sign-posting their politics/policies here.
These are spaces with particular sensitivities. Antagonising them indifferently is kinda rude at some point. Demanding that they not have their sensitivities is kinda against the fediverse at some point. Interestingly, the admin of lemmy.ml, dessalines, basically said the same thing recently.
Now, to be fair, I haven't looked into the moderation stuff that seems to have precipitated this conversation and I'm certainly open to the idea that the lemmy.ml mods overstepped (mods tend to do that IME). But my general view is that, as communists living in the west, they've probably come against a good amount superficial criticism and frankly prejudice that us general westerners wouldn't really notice, and so have pretty sharply guarded boundaries around that sort of dialogue. So they've built their own space (well platform actually), that is generally geared toward FOSS and privacy about which many of us have shared interests ... but they also have some pretty clear policies around communism that are clearly very personal to the admins that are better respected than exiled or antagonised.
Also, none of this is to say everything should be on lemmy.ml. Quite the opposite. Diversify! That's part of my point. But away from lemmy.world too, and with the understanding that part of diversification is enabling niche spaces that can cause friction and said friction isn't, in itself, a problem. Instead, IMO, we tend to get a bit feverish whenever these sorts of things spark up. Anyway ... rant over!