Try thinking like a PhsyOps warrior for a minute. You know trouble is coming but not sure where but you are pretty sure of the when. You need a cover story general enough to be used in any Middle East country and put it out before the expected date of the incident.
The Embassy in Cairo apologized for the anti Islam video before the Embassy in Cairo was attacked because they expected problems on 09/11. Turns out the story can be used in Libya also. Based on the probing attacks on the Benghazi compound prior to 09/11 I suspect that intelligence was expecting trouble there.