They are soldiers trained to kill.
Not quite as much 'overkill' as 100 rounds from the A-10's Gau-8, but, if you watch the film, you'll note there were not much identifiable remains left.
IMHO, our PsyOps guys should make up a DVD of clips like this -- and sell them in the same Iraq marketplacess where the terrorists sell the DVDs of their beheadings of helpless prisoners. The voiceover should say, "You are next."