It's a fair bit more complicated than that. They could choose to show all of the "you're a nerd!" videos to youths in other nations and all of the "look at what I did using science and engineering!" videos to youths in their own nation. It might be considered that such a move would put them in a more competitive position years to decades down the line.

No you said a comparable dataset to TikTok was commercially available.

Few random webcams which would be illegal to take video from is not substantive and does not provide any insight into their interests, likes etc.

The whole issue with TikTok is that the Chinese government is able to personally identify people who disagree with them.