Financial markets can be manipulated provided you have the right keys. At this point in time, this is just a wild conspiracy theory and it's explained as retaliation for all the cyber attacks allegedly carried out by the Chinese govt or people affiliated with it.
There's plenty of reason to believe China was in a bubble long before these last couple of weeks, and if you don't like somebody and want to do them the maximum damage, you want to help inflate the bubble, not pop it. (Well, at least, if you have a rational view of how markets work.)
