While the US is a major market, but it's not the only-one. Isolation policies do not work in a globalised economy, China isn't trying to isolate itself, the US is.

If the US pulls this sort of erratic crap with one of its major trade partners, others will go look for alternatives too. Yes this will hurt China, but I think you underestimate how hard this would hit the US. This is the next economic crisis in the making, and at least some people in the US government seem to realise this, since the best solution for boosting the economy is going to war. Hello Iran?

This is not China that is at fault, it's the US that's being a little cry-baby.