Seen it before. At the risk of being labeled a war mongering, slobbering, insensitive slob, that video was produced strictly to hit you in the gut. But, if you watch it, and not very closely, I might add, you quickly realize that you cannot make any judgements about the incident based on that one, heavily slanted bit of tape.
There are too many unknowns about that incident. We don't know what came before or after the incident. More to the point, the tape was edited so heavily and in such a ham handed fashion, we can't even determine what really happened during the part of the tape we watch. I can think of a hundred circumstances that might make that bit of tape seem less inhuman. But, in the rush to judge, we accept whatever the editor of the tape wants us to believe. Like a magician, with a little slight of hand and misdirection, poof! We've murdered an Iraqi in cold blood.