The date was not a coincidence. A two-bit youtube video by previously unknown people unrelated to the US Government was not the reason. As reported by a former member of the Muslim Brotherhood, Walid Shoebat, the advertisement for the "protests" was this:
"This demonstration was about one thing – creating havoc to apply pressure that would lead to a change in Egyptian Constitution by Nour:
"Salafi Nour Party officially joined the Commonwealth of ‘voice of wisdom’ with Wisam Abdul Waris, as well as with Nader Bakkar, the party’s official spokesman and Dr. Ahmed Khalil Khairallah, member of the supreme body."
"Ahmed Khalil of the supreme body and I joined the Association of the voice of wisdom with Dr. Wisam Abdul Waris as official representatives from Nour Party and the Salafist call."
Bakkar then added that the association…
"…aims for legal prosecution for anyone of harm to Islam at home and abroad"
That explains the reasons for Islamist extremists to desecrate the US Flag and hoist the black flag of Al-Qaeda. The Nour Party controls 20% of the Egyptian parliament, with the majority being the Muslim Brotherhood.
"Debkafile’s counter-terror sources report exclusively that far from being a spontaneous raid by angry Islamists, it was a professionally executed terrorist operation by a professional Al Qaeda assassination team, whose 20 members acted under the orders of their leader Ayman al Zawahri after special training. They were all Libyans, freed last year from prisons where they were serving sentences for terrorism passed during the late Muammar Qaddafi’s rule.
In a video tape released a few hours before the attack, Zawahri called on the faithful to take revenge on the United States for liquidating one of the organization’s top operatives, Libyan-born Abu Yahya al-Libi in June by a US drone in northwestern Pakistan."
The War on Terror has not "ended," and it will not end by retreating from an enemy that attacked without provocation, and despite the US ignoring its declarations of war in 1996 and 1998.