That’s what happens when the communists are purged and billions of propaganda dollars are spent over generations to erase their memory: you end up with Newspeak, where people don’t know their asses from their elbows. https://en.wikipedia.org/wiki/Red_Scare
There is not well-documented evidence. There is garbage, Cold War II propaganda “evidence” from Adrian Zenz and from US-backed regime change non-governmental organizations.
A Reddit AMA Claiming To Be A Uyghur Quickly Exposes A CIA Asset Slandering China