There are 10s if not 100s of articles on it, and even a paper written about it: https://as.nyu.edu/content/dam/nyu-as/politics/documents/The.... One does not have to be in China or observe it personally to know of its existence.

Okay, so from the one you linked:

>Respondents who are the most highly educated, have the highest number of daily posts on social media, and spend the most time on social media, appear to self censor criticisms of the government on social media more than they self censor praise of the government on social media. Other respondents do not appear to self-censor criticism of the government on social media. However, my findings are severely limited by my small sample size.

I was actually asking for accounts of firsthand experience, not ideological slop.