Why couldn't China just do that and support revolution elsewhere?
The amount of terrorism that the USA can do against China is immense, either directly along its very huge land borders or indirectly through any other country that China is working with. As Biggay said, remember the USSR and Afghanistan? What if there were like 10 proxy wars against China going on simultaneously?
Other things are kinda sucky though, like taking a backseat on openly supporting Palestine. Then again, Chinese weaponry is winding up in the hands of the resistance, so... 