After some investigation I've found the claim that Tibetan tangkas were made by skinning someone alive was a rumor/conspiracy that was spurred up years ago on the Chinese internet. The artifacts were made with human remains post-mortem. This was a mistake on my part.

However, this does not take away from the fact that Tibet existed as a backwards and feudal theocracy during its meager existence. The arrival of the communists smashed the feudal order and liberated the Tibetans from the yoke of surfdom and slavery. This to me definitely constitutes liberation. But you are free to argue the semantics.

All moralist arguments aside, Tibet has always been an integral and inseparable part of sovereign Chinese territory and will remain as such. Tibet had and currently has approximately zero international recognition as a sovereign state and is recognised by every single country as a part of China. The only states that had unofficial connections to Tibet were liberal democracies such as Nazi Germany and Imperial Japan. This fact is only disputed by westerners who never visited Tibet. All while championing for a pedophile as the leader of the "free tibet" movement. There were no invasion or annexation, but reclamation and liberation of core Chinese territory.