It's a sad day when we worry so much about these disgusting acts performed after these men were already dead, and not question the reasoning for them being killed.
Upon initial investigation, this was done by a Marine sniper team, so I doubt they were killed in close quarters combat. I bet there will be a full investigation on finding out who did this, but they will never seriously investigate why these men were even killed. As long as they are called "Taliban" the murder will be justified. We've already witnessed countless examples of rogue U.S. military unit murdering civilians for no apparent reason. What's to say they didn't just do this because they were bored, and they weren't actually hunting down "Taliban insurgents".