I dunno, man. I'm pretty new to the whole fediverse stuff. I just learned about modlogs from this thread here, so obviously what I say is not super well-informed on the topic. But looking at the modlog someone linked below, most of the stuff I'm seeing removed are actually the exact opposite. I see comments removed because they're calling other people tankies. I'm seeing stuff removed because it's "horseshoe theoretisizing, bad-faith". Then a bunch of people indirectly advocating violence.
I've never been a mod of anything, and a lot of this looks like stuff that if it were up to me I'd leave. But I don't really see any evidence that .world "has an overwhelmingly “US Democratic Party” slant, politically". As far as there is any ideological basis behind the mod actions, it seems to be more unaligned leftist than anything else.
Again, though, I'm very new to this and did not do anything close to what I would describe as a thorough search.
I haven't been on lemmy for all that long, but this thread is the first I've ever seen anyone complain about moderation.