It would not be in the Chinese government's interests to do this in a way that preserves anonymity for its citizens and protects them from being monitored, but I do really want to see a layer of the internet where it can be trusted that every poster is a real human, or a citizen of a particular country.

I understand that this is the sort of thing cryptographers think zero-knowledge proofs could help us with, but I'd be fine with a centralized approach: a government system that provides key pairs and a verification system for its citizens that could be done during the passport application process.