So first of all, I do encourage you to go to social networks (if you still have them) and kick their propaganda accounts around. If you want to know which ones, just search for chinese news papers, particularly those who say are state affiliated. Go there, counter their narrative and see the wumao come at you for a spin.

Now, if you want them to STFU you can't defeat them with arguments, reason or logic, as they will have a "perfectly reasonable-looking answer" to counter. Your main goal isn't to win an argument, it's to make them realize they are restrained by their dictatorship and or get fooled into doing something that will get them punished by it, and this is what I saw works:

• After a bit of arguing (touching subjects like Dalai Lama, Jack Ma's disappearance for criticizing the banking system, Winnie the Pooh's ban, the Great Firewall of China, etc.), they called me a liar and asked me to "think critically".

• I requested them to show me they are allowed to think critically themselves.

• I required them to say something they dislike or criticize of: their "president", Communism or Socialism.

• It seems they aren't allowed to criticize Socialism or Communism AT ALL. Like, not at all ever. About Xi they will say some dumb shit like "I wish he was more socialist" and dodge it, but their State Religion is untouchable, so that will definitely get them in trouble.

• As an ending blow I said: "see, I am allowed to criticize capitalism, for example: I don't like the monopolies that some times get created, although I do think capitalism is the best option there is".

Have fun cracking these propagandists.