Back in the early stage of social media, US companies had the choice to operate in China as long as they comply with the censorship and local laws. Had they chosen not to quit China market at the point, they would have been probably huge in China holding major access over Chinese users too. (How would Chinese government react to that is something we never get to see now...)

I keep seeing argument regarding "China bans social medias from other countries". It's not an outright ban saying that "Facebook cannot operate in China", but more like "Comply with the censorship rules or you cannot operate in China". It's not targeting "ownership" or "nation states". e.g. Google chose to leave, while Microsoft continues to operate Bing in China.