The preoccupation with attempts to prove the insincerity of the anti-Japanese demonstrations by demonstrating their government links is, I believe, a dangerous distraction.
Because it seems to imply that, if the demonstrations are government-organized/facilitated/supported/condoned, they can be dismissed and, if the demonstrations are removed from the equation, the PRC's strategy on the Senkakus/Diaoyu can be dismissed as a futile exercise in Astroturfing (simulation of a grass-roots movement).
This, I think, draws from the preconception that impassioned popular demonstrations against authoritarian regimes in the Middle East, in Russia, and in China are the only ones that matter, and if they advance the agenda of authoritarian actors, they can be ignored.
However, the regime's intention is not to try to manufacture a false Chinese simulacrum of Tahrir Square.
I believe the CCP is sending a series of messages to Japan and the United States via these demonstrations, and to send the message it is important that everybody is aware that they actually were state-managed.
First, the CCP is determined not to back down in the Senkaku/Diaoyu conflict. Although Japanese Prime Minister Noda stepped in to purchase the islands as a conciliatory measure in order to short circuit a carnival of provocation planned by Shintaro Ishihara, the governor of Tokyo, the CCP whipped up anti-Japanese sentiment and demonstrations on the announcement of the purchase regardless, in order to demonstrate its deterrent capabilities in economic and diplomatic warfare or, in old-fashioned terms, fire a shot across Japan's bow.
Second, China does not intend to provoke a military confrontation at the islands that would viscerally alarm Japan's populace and elite, and allow Japan to deploy its unanswerable geostrategic advantage: the military alliance with the United States. China's provocative movements in the waters around the islands are carried out by maritime surveillance vessels and fishing boats, not the navy.
Instead, Japan will be confronted at its most vulnerable point: the economic interests of its corporations and the well-being of its citizens inside China.
Third, the CCP is conveying that it can manage the unrest that goes hand-in-hand with a mass campaign, and will be prepared to escalate the damage it inflicts on Japanese businesses in China as needed despite the losses suffered by the Chinese economy and Chinese employment.
Finally, the ultimate purpose of the furor over the Senkaku/Diaoyu Islands is to demonstrate that Japan must rely on accommodation with China, as well as its alliance with the United States, to achieve peace and prosperity.
With this background, US Secretary of Defense Leon Panetta's recent remarks in Japan can be taken as an acknowledgement - at least for now - of the limits of American power and the challenges facing the pivot into Asia:
The United States, in all cases of disputed territory involving Pacific waters, urges "calm and restraint on all sides," the secretary said.
"United States policy with regards to these islands is well known, and obviously, we stand by our treaty obligations," Panetta said. "But the United States, as a matter of policy, does not take a position with regards to competing sovereignty claims."
In other words, the threshold for active and open US involvement in the controversy is a military clash over the islands between Japan and China. Short of that ...
Panetta's remarks are not a matter of throwing Japan under the bus, but they do reflect the reality that there are limits to what the United States can, will, and wishes to do about the Diaoyu/Senkaku islands. And they reinforce the signals sent by the Chinese demonstrations.
It looks like the Japanese government - at least the current, relatively cautious and non-confrontational government, which may not be in power very much longer - got the message:
"We do not want anything that would affect the general bilateral relations between Japan and China," Chief Cabinet Secretary Osamu Fujimura said at a press conference Tuesday. He emphasized that the government has paid special consideration to China, in putting three of the five islets under state control.
The government will not construct any port facilities as shelters for fishing boats or improve the lighthouse, but keep the three islets as they are, at least for the time being.
It would appear that, at least for the time being, China has come up with a diplomatically and economically costly but effective pushback to the cycle of provocation that was driving the Senkaku/Diaoyu confrontation. If and when the Noda government falls and is replaced by a new hardline Japanese government with a mandate for confrontation with China, the US will be trying to hold it back, not egg it on.
The anti-Japanese formula may also be applied to dealings with Vietnam and the Philippines over the South China Sea disputes.
In other words, China's anti-Japanese demonstrations are not a pathetic charade. They are dead serious - and successful.
TLDR: China did the protests so that it could show it had leverage over Japan that was non-military (the safety of Japanese investments/trade with China and the physical safety of 125,000 Japanese citizens in China) and that the United States could not affect or stop, weakening the US's credibility as a guarantor of Japanese security and forcing Japan to always consider China's interests when making any further moves in East Asia.