The justifiable reason was politics.
Obamas whole foreign policy would have looked horrible if they had admitted an Al Queda attack. They were supposed to have died along with UBL. Hillary also recorded the stupid "we came, we conquered, Khaddafi died" comment.
I dont get this. Is obama's entire foreign policy a failure because of one terrorist attack? For me, 1) bin laden is dead, and 2) we didnt start any trillion dollar wars, so he at least gets a C.
His drone war certainly is a negative to me, but Romney thinks its been a success so not much choice there