Ok, What Does This Mean?

Thousands Join Anti-Japan Protests in East China

In the third weekend of violent protests against Japan, thousands marched on the Japanese consulate in Shanghai, smashing its windows with rocks, pelting it with paint bombs and attacking Japanese restaurants along the way.
One banner read "Face Up to History." Another warned: "The anti-Japan war is not over yet."

Since I'm paranoid by nature, and as I'm of the belief that the only people who get to protest in China are the people the Chinese government allows to protest, what is the Chinese government saying with this? Why would the Chinese government be trying to pressure Japan?