For a community that is so actively political, the tolerance for an open exchange of views is surprisingly low.

I'm not over much of that activity, but I think the more accurate way to think about it is that they're actively communist, and actively critical of the west and its imperialism/captialism. So they're coming from a pretty different perspective than middle/centrist westerners and find some of the presumptions/beliefs of westerners outright awful lies. Whatever the truth is, they're not trying to run a perfectly open forum to try to convince everyone of communism, when it comes to politics that is. So anything that starts with a critical view of China is immediately viewed suspiciously and likely to get moderated (depending I'd say). I understand how many would find that problematically censorial. Thing is though that they hold a minority position that tends to piss a lot of people off, so a good amount of defensiveness is just a natural consquence I'd say. In my experience, the worst part about their communist beliefs have been all of the loud anti-communists they've triggered.