Yes, indeed. Krauthammer rightly called that "the fourth scandal."
Two plausible explanations have been suggested for this curious scandal.
1. The Ambassador, who had a record of working closely with the terrorists during Obama’s war against Kaddafi, had agreed to be “kidnapped,” so Obama could arrange a trade for him and the Blind Sheikh, thus pleasing his Muslim allies while having a great October surprise in the run-up to the election.
2. The Ambassador was in the area to pass weapons along to the terrorists for use in Syria and elsewhere, under the pretence of trying to STOP the flow of weapons into terrorist hands.
It seems perfectly plausible that BOTH of these explanations could be true. First Obama tried to keep all the defenders away so the ambassador could be quietly kidnapped. But that plan was disappointed. The terrorists assumed that they had been ambushed and betrayed, so they raped and murdered the ambassador.
Subsequently, after the violence had broken out, Obama decided to continue refusing any help, in order to let the ambassador be killed and prevent anyone from getting too near the site until any possible evidence of what happened had been destroyed.