OK I saw the video and here's a few facts to consider
1- the insugent was thought to be dead
2- they hadn't been searched for weapons
3- a marine had been killed the day before because an insugent had booby traped his body with explosives.
4- someone shouted "He's faking being dead!" as the insugent started to move.
Knowing this I think anyone who tries to malign the Marines with this story should be ashamed of themselves.