Similar to the situation in Tibet, the source of the ongoing conflict in Xinjiang is that the Han and the Uyghurs have incompatible interpretations of the history of the same territory. The Han are passionate that Xinjiang is an integral part of their sacred Chinese Motherland. The Uyghurs with equal passion see their East Turkestan homeland as illegitimately colonized by a foreign power. This is a question of recognition of identity, the stuff of men's souls. People are irrationally ready to sacrifice their lives for genuine recognition of their religious and cultural ethnicity and to assert the political destiny of their national identity.
China's policy has been to engender economic development in Xinjiang as a means to bring the Uyghurs into the great project of China's Han-led rise. But exactly contrary to the Chinese Communist Party's expectations, the more Uyghurs achieve middle class standards of living, the more Uyghur nationalistic they are likely to become.
In the meantime the level of anger reaches a fever pitch and violence ensues and there is terribly bloody death and destruction.