Col. Patrick Lang has the best analysis I've seen yet.

It is sadly amusing how much people do not want this to be about the man's religion or his Palestinian ancestry.

His relatives understandably want other Americans to believe that he was traumatized by listening to soldiers' stories about the wars. They certainly don't want people to think that there was anything about the atmosphere in his father's house that caused this man to reject the land of his birth and the obligations of his oath.

The media flacks have now been conditioned into political correctness to such an extent that they can't bring themselves to suggest that his Islam or his sense of grievance about American wars in the Islamic World had anything to do with what he did.
Read the whole thing.