Is it more likely that they want people to have nice passwords so set up filters to make sure, or that they know everyone’s password because they want to be able to see what all of China is saying to each other? I’ll continue to believe it’s the latter unless I see a better explanation.
It's highly unlikely they need folks' passwords to "see what all of China is saying to each other". I'd fully expect the Chinese government to have full access to that, without any need for a password.
Unless they assume the average Chinese user is just like the average user everywhere else on the planet which tends to reuse password in multiple locations.
Because the CCP is a totalitarian state with an interest in controlling expression, even in passwords?