Some source to backup this number? Are they actually in prison?

IMO the fact that we should be skeptic about China official stats means that we should also refrain from throwing random numbers at the wall hoping it will make China look bad.

BTW, two wrongs don't make a right, it's not about what they do wrong, it's about what we do better, like for example, is Guantanamo acceptable in a western democracy?

Probably those are not on the “stats”

This is what a walk down the street in Urumqi looks like: [0].

It's possible to talk about Xinjiang without going over into hyperbole.

0. https://youtu.be/_OMaUIC4Om8

Do you seriously believe that all 12.8 million Uyghurs in China are literally imprisoned?