In Chinese perspective these are acts of international terrorism related to islamist jihad (ISIS, Al Queda etc.). And talk about Xinjiang seperation from China would be what we in the west call "hate speech" since it possibly would entail cleansing of Han-chinese from the region.
However this perspective is not shared by the west which is probably why the Chinese government cannot get the same services from Google and Facebook that countries like USA or France can when comes to censoring hate speech or get logs on suspected terrorist.
Hence they have to resort to more primitive ways.