I think 0bama / Stevens were supplying Ghaddafi’s shoulder fired anti-aircraft missiles through Turkey to the “Rebels” in Syria who just happen to include a bunch of Al Qaeda.
That explains everything.
Why not allow any of our planes to flyover in support? Because Al Qaeda below you in Libya has MANPADS (anti-aircraft missiles) that WE SUPPLIED THEM.
Why is the Administration so desperate to suppress the survivors, and all information about Benghazi? Because supplying anti-aircraft missiles to Al Qaeda is EASILY UNDERSTOOD TREASON.
It all depends on the success of framing the situation 'correctly'. All that they have to do is point to the American history over the last century or so of interfering in other countries and installing people worse than the ones replaced. Not every time, of course, but often enough.
Look at Afghanistan, for instance. The Taliban had mostly eradicated opium production and institutionalized man on boy rape. Not saying that the Taliban should not have been tossed out, but why oh why aren't we a bit more choosy in the people we install?