Why should Tibet be free from China?
You need to study Tibetan history if you want to take an informed stance on historical grounds. Tibet has never “been a part of China” before the Chinese invasion in 1950/51. That claim is solely based on modern ideological reinterpretations of history. Let’s take a quick look at the history of Chinese-Tibetan relations. Before the Yuan dynasty Tibet and China were two powerful, competing empires. In the 8th century Tibet actually occupied the Chinese capital, Chang’an (today Xi’an), dethroned the emperor and nearly defeated China. The wars ended in a stalemate and a peace treaty in 821/822, where both countries vowed to stay out of each others land forever, that the Tibetans should stay in Tibet and the Chinese in China. In the 13th century, when Tibet was a weaker country, they formed an alliance with the Mongols, where the Tibetans became religious patrons of the Mongols in exchange for political and military protection. Later the Mongols invaded China and founded the Yuan dynasty,
