The first and most important thing is that they transferred a large number of Chinese immigrants to the area. They take over the jobs, and they take the lands and the farmland, everything, from the Uighurs, so there could be some social unrest. In order to prevent that social unrest and silence it, they are taking very extraordinary measures. They are killing and intimidating. They're threatening them, telling them not to do anything that shows resentment of the new Chinese immigrants.
The second important reason is that east Turkestan is the energy hub for the Chinese government. Not only is there plenty of energy, but at the same time there is the energy windfall from central Asia as well. By transferring large numbers of the Chinese population to east Turkestan, Chinese ambition is expanding into central Asia to control central Asia as well as to destabilize them in the future.
Third, sadly, the Chinese government is using this kind of Uighur issue and the Tibetan issue just to change the national agenda and to bolster the nationalistic view of the Chinese. They do it from time to time when they have an internal crisis, a domestic crisis elsewhere in the Chinese provinces. When they are persecuted.... For example, I gave you a number of shooting cases, all of them well reported, but the Chinese don't report them. They don't provide this kind of information to their domestic audience.