China is convinced that Taiwan would not have done this without tacit American approval. They see the U.S. promise to defend Taiwan after the declaration as proof of this proposition. In Chinese dynastic history, numerous insurrections have originated with apparently apolitical sects generating hostility to the regime. In fact, the Chinese are setting up a campaign against a new group, Xiang Gong, which is said to have 30 million members. The Chinese government does not regard the rise of internal opposition as accidental.
China is still in economic trouble.
Regimes cannot afford to appear to be weak, particularly when they are. The issue here is how Beijing appears to the Chinese masses. That means that quiet diplomacy that wouldn't give Beijing a public victory is not going to happen. China sees the U.S. as having put into place policies that, if followed logically, would result in U.S. participation in the fragmentation of China. The one legacy of Mao that all Chinese value is that he eliminated the foreign domination and fragmentation of China that had existed for a century.