As someone who just came from China after living there for nine months, I think the better way to put it is this: you can talk about whatever you want, but if you make an effort to organize, initiate, or participate in a public discussion concerning a taboo topic, then you are putting yourself at risk.

It's the appearance of an organizing that is really taboo. Of course please take my opinion with a grain of salt. I am a foreigner who was there less than a year.

A young girl (10? 12?) was a famous streamer than sung a line from the national anthem in a sing-songy way and was jailed for 'making fun of the nation anthem'. You can see the exact moment she realizes she messed up.

advchina/serpentza/laowhy86 are the canaries in the coalmine atm.