It's pretty telling how effective China thinks it is, given their restrictions on Douyin ("internal Chinese TikTok"). iirc kids can only use it for <1 hour / day.
China thinks its effective at wasting time. Children also aren't allowed to play video games monday through friday, and are limited to 1 hour per day otherwise- a law which existed before douyin limits: https://www.bbc.co.uk/news/technology-58384457
The country that is obsessive about its children and their productivity, the country famous for kids competing in chess and abacus and piano... that country is just banning douyin because it's a time waster.
I don't think encouraging national unity and encouraging strife and polarization are the same thing at all, and in fact I would bet the latter is easier at scale
Maybe they're restricting Douyin because it's a timewaster, maybe because it much more naturally encourages discord than unity. Maybe both. Probably both, frankly.