Since when did the wounded get special protection ? Lets get real - it's one thing for grunts who have over-run a position to make provisions for the wounded, but quite another for a helicopter to just let someone escape. If they were convinced that he was a legitimate target (and from preceding posts it would appear that he was) then the crew did a good job. Better they eliminate a hostile, than that chap next day puts an RPG through their rotor disc.
Personally, I thought it was great.