As somebody who's visited both Japan and China multiple times, I find the orchestrated violence from the Chinese against the Japanese pretty reprehensible.
While nobody's hands are absolutely spotless in this area, this simply isn't the time to gin up the violence.
China is where it is today- in positive as well as negative ways- due to Japan. Japan has invested very much to make China competitive.
The US, if it were truly an honest broker in the region, would be able to defuse this situation.
But, then again, the US is playing this stuff for its own benefits.