I finally watched that one Britmonkey video about everything banned in China after avoiding it for years, and they claim that the word "disagree" is banned on Chinese social media.
He also claims that they banned the letter "N" kekw
It also seems most commenters didn't watch the video either. The claim isn't that those words were permanently banned, it's that they were temporarily removed (blocked) from search results untill people calmed down, when they were allowed again.