Seems you missed my point:

Again: how does China stop every single Uyghur adult from taking pics with their smartphone?

Not “every single Uygur”, just the ones locked up. That is how detention works, even in the West.

So there was the BBS and the PBS report another person provided in the comments.

By the way, I agree there was no genocide. See my other comments where I acknowledge the Uighur separatist movement threatening access to the Sil Road so obviously the CCP has to try something.