I have been a practitioner of Tibetan Buddhism for many years, so I have course have a vested interest in these stories not being true. No doubt life before the Chinese conquered Tibet was not as rosy as many of us have believed. But I would be extremely skeptical of your sources.

All of them are in the pay of the Chinese government, and have strong motivation for lying. And the Chinese government lies a lot. They have said many things about Tibetan Buddhism that I know for a fact aren’t true. (That they practiced human sacrifice, for example.) They pay large numbers of people to post critical statements about Tibet and the Dalai Lama on discussion boards. One of your sources says 98% of all Tibetans were serfs, but I have seen other sources say that a fifth of the male population were monks. Obviously both of those can’t be true.

Finally, if Life was so terrible before the Chinese, why does one of your sources say that "Despite a campaign of "patriotic education" that since 1997 has defrocked hundreds of monks and closed dozens of monasteries, support for the Dalai Lama, the exiled religious leader who is the target of the campaign, remains sky-high". Why does the Chinese Government forbid foreign travelers from talking to Tibetans? I don’t know the answers to these questions, but they are among the many good reasons for being skeptical about these Chinese sponsored sources.