BTW I find it disheartening when other leftists don’t seem to understand the concept of critical support, and act like they have to justify anything and everything a government does simply because they otherwise support it.

I find it disheartening when people talk out their ass on a subject they’ve only learned about from cultural osmosis, and they then think the pushback they receive is due to some doctrinal orthodoxy and not just because they’re talking out of their ass. People aren’t agreeing with your criticism because it is unfounded, not because it is criticism of China. If you posted something incorrect about the United States you’d likewise receive push back, and thats not because people here are nationalist democrats, but because that incorrect thing would likewise be unfounded.
You will see plenty of actual critique of China, especially its foreign policy, its trade with Israel, its actions during the sino-soviet split, it’s failure to curtail liberals, the regressive views of some of the old guard when it comes to queer people, its drug laws, and Im sure a bunch of other things as well. You will also see spirited discussion about things like the “great firewall”, state censorship, Dengism, and I dunno what else. The fact that things aren’t reduced to some simple binary “good/bad” is why you see this. Because, you know, things aren’t that simple.