I don't think they're banning it because it promotes what China wants. I think they're banning it because it doesn't promote what the US wants. The US is not offended that you can't criticize Tiananmen Square. It's fine whether you can or can't criticize Tiananmen Square. Only China cares about that.

The reverse also happens - Gaza being the main one. China couldn't give two shits about what happens in the middle east - it's not involved at all. So it lets footage be played sometimes. But the USA cares deeply about making sure young people don't see footage of Gaza and that's the sort of thing that motivates the US to ban this app.