I am a big supporter of your historical debunking of claims that white people are responsible for all the evil in the world. However, I don’t think this example helps your case very much, because it also inadvertently supports another example of evil non-white people: the cultural and biological genocide of Tibet by the Chinese communists. We could go back-and-forth about which side was worse, but that seems pointless as the evils on both sides equally support your case.

I could point out that, even though those articles are western sources, They are all quoting people who now have a vested interest in supporting the Chinese regime. I could also point out that this regime has a long history of jailing people that says things it doesn’t like, and spreading lies to justify its conquests. you don’t need separate evidence to falsify specific claims when your source has been proven to be unreliable on other claims.

I could also refer you to Jonathan Brown’s book on Islamic slavery, which shows the hopelessness of any attempt to prove Tibetan Serfdom is “really” slavery. The Mamluks, unlike the freed slaves in America you mention, were still slaves, even though they were rich,powerful and owned slaves themselves. They were in many ways “freer“ than many so-called non-slaves. (like American sharecroppers who couldn’t leave their land because of debt). That’s why the fact that the Tibetan serfs were “sort of like“ American slaves doesn’t help your case very much. You can’t make the two categories equivalent by citing facts like one monk raping somebody. Non-slaves get raped all the time, which is terrible, but that doesn’t make all rape victims Sally Hemmings.

But rather than quibble over details, let just be honest that you have an agenda (which I support), and that these sources are too tainted and questionable to serve that agenda, even if some of these claims are true. I would suggest that you drop this issue and go on to the numerous examples that support your point unambiguously.