The thing is, even a failed rescue attempt is better than none, politically. It shows you tried not to leave anyone behind. People understand that in the fog of the situation, not all rescue attempts succeed. But we want the military to try.
I think this is oddly related to Obama being anti-life. He really does think some lives don’t matter as much as others, I guess. Our culture, at its gut level, does not view it that way.
I think it possible that he thought the lives of the attackers were more important than those of the defenders. Remember his anti-colonial roots.
I’ll betcha if the Ambassador was black he’d done a rescue. Wanna bet?