You’re absolutely correct. Nothing like this could happen without authorization from the Chinese polituro. They were sending a message. There was no danger to the Ambassador, but it was an “in your face” insult at a time when Americans (if not the American government) still have an open wound because of what happened in Libya.
As a Chinese strategist once observed, “Now, when your weapons are dulled, your ardor damped, your strength exhausted and your treasure spent, other chieftains will spring up to take advantage of your extremity. Then no man, however wise, will be able to avert the consequences that must ensue.”
Our strength, in a great many ways, is exhausted. It was only a matter of time before ‘other chieftains’ began to capitalize on our weakness.