Haha, look, I don't think killing people is all that great. But killing people is unfortunately the only realistic way to solve certain problems.
What were the realistic options here?
1.) Have him repent. Not going to happen.
2.) Go and get him, capture or kill. That's going to get your Elite (people the country actually values, unlike this POS) quite possibly killed, with a decent risk of an incident like an Elite captured and then public dissemination of them torturing him, forcing fake confessions, beheading, or just holding him and releasing teaser videos.
3.) Kill him remotely.
If no civilian casualties, who would be F'ing stupid enough knowing what this guy is about and knowing what kind of war we're in to go with option 2, and even if the capture - instead of kill - goes smoothly, go through all the trial BS in a civilian court?
BHO made the right call here (and that's all he did, was make a call, for all you BHO fellate'rs), and then the system that the evil "Bush&Co" setup took care of the rest.
The end.