We were shipping arms out of Libya to Syria to arm ISIS, FSA, the people not quite as bad as Assad (at least we thought so at the time, who later turned out to be much, much, much worse.).
Us doing that would have violated the arms embargo to Syria, embarrassed the Turks, and the Libyians (at least the ones nominally on our side), and whoever we were shipping the arms to in Syria, who were pretending to be on our side. McCain's ahole buddies there, remember??
The whole "He was negotiating a lease for a Consulate." Bushwah cover story? I'm sure whoever the owner was of the building that was originally attacked would have been more than happy to continue his European Vacation on our dime, given that his country had gone all Mad Max. (Thanks Hillary !!!)