The thing I probably find most annoying about most Western reporting on Western China is how they make it sound as though the whole place is little larger than downtown or Belgium or some such.
Xinjiang itself is about the same size as Europe and the main population centres are great distances from each other, not every non han ethnic group is a Uighur and given the distances it is unlikely that ethnicity will count for much between communities living hundreds of miles apart.
Simmering tensions? If Xinjiang is a pot then the population centres are just a few drops scattered around the base. Aksu and Urumqui are about what? the same distance apart as say Rome and Berlin or maybe New York and Chicago. If you heard about hit and run incidents in these cities maybe a year apart, would you assume that they were somehow linked?
Separatism is certainly overplayed and XInjiang borders an unstable region. There is criminality in China just like anywhere else and major criminal opportunities in Central Asia
1) People Trafficking from Central Asia into China - Hollywood may still love portraying Chinese as victims locked in Sea Crates trying to enter the USA, but in the real world China is a promised land of wealth for millions and they would love a share and escape problems such as Afghanistan Tajikistan etc
2) Gun Running - Insurgency, Civil Unrest and Fundamentalism across the border well what more do you need to know. To quote a classic exchange between Del BOy and granddad from only Fools and Horses
Del Boy "You were caught trying to smuggle guns into Spain during a civil war"
Granddad "Yes Del, its the best time to do it"
It certainly is.
3) Drug Smuggling - Pakistan and Afghanistan are bang next door and produce must get to market and use any possible route. Its a big problem in China just like in Central Asia and Russia.
All of these things are big money enterprises and resent too much police snooping in their lucrative affairs. These go on all day every day while for most of time Separatism barely registers.