A bus attack in China was performed by an Uyghur separatist group (see Uighur Group Claims Bus Attacks). Many have heard about Tibet being oppressed by the Chinese. However, to the north-west of China is another autonomous region called Xinjiang, which is made up of many Uyghur people.
The history of humankind is filled with people claiming that certain groups should separate. Not only do Tibetans claim this but so too do Scottish people who want to be separate from the British.
Although I personally think that the CCP's treatment of Tibetans is horrific, I do not think any group of people should simply separate. The problem lies in the definition of a people. Many nationalists claim that all groups should have sovereignty over their own land. However, these people never define what a people is. They never define what an ethnic group is. Looking at the issue objectively and scientifically, it is clear and obvious that due to subjectivity there is no such thing as an ethnic group. There can be one or infinite groups of people depending on who you question. If in theory there can be infinite groups and if the nationalist ideal of giving all groups sovereignty and territory is met, then what we will witness is constant splitting. For example, if Tibetans control Tibet, one group of Tibetans will claim that they are different to other Tibetans and will demand separation. This continues ad infinitum. It is impossible for infinite groups of people to share finite land.
Does this mean Tibetans should be tortured and oppressed by Chinese Communists? Certainly not. Just because we cannot draw lines between ethnic groups, it doesn't mean we cannot draw lines between individuals. It is difficult to know where an ethnic group starts and where it stops, but it is relatively simple to know where an individual starts and stops. Demarcation of individual identity is achieved using the skin. Everything within my skin is me including my heart, my brain, my lungs, etc. Everything within your skin is you. Because it is so easy to define the individual, we can easily set up political systems that give freedom to the individual. These freedoms exist in many countries that emphasize individual liberty such as the United States and the United Kingdom.