Someone finally came through with evidence on this talking point.
The CIA knew it was an al-Qaedalike attack from the start.
Political appointees in the State Department
Lawyers (see edit May 21 below) forced the CIA to change their public assessment because
it could embarrass the White House
other TLAs told them to. Then Obama and top officials and spokesmen spent several weeks telling a made-up story that the attack was merely a protest about a Youtube video that got out of hand.
There are still many open questions about this incident, but that answers one of them.
Edit May 8: It may be worse. Deputy mission chief Gregory Hicks says he was demoted after privately questioning the Youtube story. By my understanding, Hicks was the #2 man in Benghazi behind the dead Ambassador Stevens.
And worse: Mohammed Magariaf refused to cooperate with US investigators for more than two weeks after Barack Obama undercut his credibility by claiming it was not a terrorist attack after Magariaf had said it was.
We have also learned that two units were explicitly denied permission to intervene, but not that either was in a position of changing the night's events. One was a group of four soldiers in Tripoli denied permission to hop on a jet that was already going to Benghazi, but after the four victims were already dead. The other was a Foreign Emergency Support Team that was some distance away from Libya. The story at this point sounds like a communications snafu; my guess is that the NSC met at an early time and decided that no action was necessary at that time, then broke leaving standing orders to do nothing which were followed as the consulate was attacked again throughout the night.
Edit May 21: More of the email dialogue has since been published. The turning point came at 4:20 PM (pg. 14) when CIA General Counsel (top lawyer) Stephen Preston referred to "express instructions from NSS/DOJ/FBI that, in light of the criminal investigation, we are not to generate statements with assessments as to who did this, etc. -- even internally, not to mention for public release." Thereafter, at 4:42 PM, the CIA's chief of media relations changed the CIA's assessment of the event from from an attack to a protest that turned violent. All other suggestions that an attack took place were later excised
by a team of seven, including six officials identified by name as part of the CIA's Directorate of Intelligence and National Clandestine Service (whoops) plus Obama speechwriter Ben Rhodes.
So were Obama and his people merely acting stupid as a tactic to prevent the attackers from knowing that they were being investigated? If so, it hasn't worked; no one has been arrested, and the fake protest story harmed rather than helped the investigation. Were they deliberately misinformed by the executive? That would be astounding irresponsibility on the part of the middle executive; leaders need good information to make good decisions.