The full context isn't being shown. What was this poor, abused, murdered (sarcasm) SOB doing 5 minutes before he got his virgins? I'm sure he wasn't preparing dinner for the Marines. Unless of course a new model AK-47 converts into a field kitchen.
He's a terrorist who received his reward. No one is disputing that. Their objection is that before you can shoot a wounded terrorist, you've got to open up the engagement manual and go down the checkoff list to make sure it's legit.
The imbeds are really a pain in the ass anyway, and ought to be banned. This soldier probably did it because he was playing to the camera. He wasn't smart enough to realize that it would be used against him. My guess is that the terrorist was already dead.