Standard policy is for standard situations though. Not missions in a wartorn country patrolled by Islamists with zero escape routes and tons of preliminary warnings.
Literally any of us would look at that situation and say "Wow that is totally inadequate." Why couldn't the people responsible for such decisions? And have they been relieved of their positions?
The mission was overrun and the ambassador killed. I just don't see how that can't be called a security lapse.