Those who read the China Daily may recall an article of some 3 years ago where the head of the CAAC (a former CA pilot himself) was commenting on the future of foreign pilots in China.
The thrust of his comments was that foreign pilots will have a role in the PRC airlines for the foreseeable future however they would only be the 'good pilots'. Aspertions had been made (by local pilots, and not totally unfounded) about the quality of some of the incoming foreigners. As the supply of rated pilots dried up, they got closer to the bottom of the barrel.
What you are seeing is one of their typically inappropriate responses to the perceived problem.
See:
Skies too friendly for foreign pilots- China.org.cn