Benghazi was also secure.
Benghazigate Congressional Report: Obama Inc. Lied About Video, Hillary Knew About Inadequate Security
The guards were members of the February 17 Brigade, a militia linked to the Muslim Brotherhood. Despite being hired to guard the consulate, the militia members were apparently supposed to be armed and trained by the US consulate. The State Department, instead of providing proper security, was using the consulate to train Islamist militia.