At this point it seems the best course of action for China is to be quiet and not respond to the RIMPAC, sink your islands claim, sensationalised American articles claiming various things. Just get on with business as usual. One side wants tangible gains the other wants to prop up their image. There's a win win situation here. The longer this is kept up, the less likely the US has any realistic means of stopping PRC from eventually taking her claims. No group of nations in the region can even hope to challenge China economically or militarily and they don't have a reason to do so. It's not like the PRC is moving around invading sovereign nations and murdering their citizens like a colonial power. They are simply taking what's their's and PRC's claim to SCS islands is certainly as strong if not considerably stronger than Vietnam's, Philippine's, and Malaysia's. Those three have basically zero claim (based on fact, history, precedence, international law, sovereignty) apart from this zone should be international waters. Sorry but those islands were NEVER part of their national sovereignty throughout known history. So the only reason for the gang up claim is to take it away from China's hands. Except these islands have actually been first officially chartered and officially discovered by the Chinese (written records). Which already puts China's claim in front. Now that Vietnam first started pouring concrete and tried their pathetic attempt at building islands China thought why not play just as dirty? Japs want to unilaterally sell an island that is disputed to a private citizen, well China can play that dirty trick too.
It must be remembered that these other asian nations tried pulling the dirty when China is happy to "let disputes be settled with the wisdom of future generations" (paraphrasing Deng) but its magnanimous attitude is commonly considered weakness and taken advantage of by less well-natured leaders. If they don't want the carrot, they can have the stick. China's the one with the tools this century and it would be a shame not to take complete advantage of political and military might. China behaves like a saint compared to the horrifically evil colonialists from the west who went around murdering millions around the world... often times just out of spite. So let's not compare the two.