So the DC sniper dude was a fluke of mythical proportions? Most of the dozen or so people that caught one of his bullets are dead.
Uh duh, using a scope on someone standing at a bus stop or filling their tank (non-mobile) tends to help put a round in a spot that will kill the target. When you squeeze the trigger on a SAW or M16 in combat you don't always have the time to aim for headshots. When you hit them in the trunk of the body, the minimal damage done to drugged up jihadi's is like a pinprick. They remain a threat until hit in the head or heart, or until you've put enough ventilation in him to make him look like swiss cheese.
Now if we had the luxury of a (dialed in) scoped shot, we too would have been one shot one kill. It's a little difficult though when you need to provide covering fire for a bunch of unarmed civilian truck drivers and you have to cover from your 7 oclock to your 11 oclock, while the occasional RPG comes at you from your 3 oclock.