"China" is just not a valid reason. I mean, they've still got a lot of other trading pairs availble on their site...
Agreed, the reference to China is a really odd explanation. I don't buy it. I think that there are two potential reasons why they didn't open BCH trading: 1) Volume is dropping on BCH pairs where it is still trading. Maybe they don't think the market will generate enough volume to justify adding it. 2) We are less than two months away from the Segwit2x fork. Maybe they'd prefer to see resolution of that before deciding which fork (if any) to support.