God Bless America...in The Hurt Locker

This scene from the Hurt Locker employs fast and slow cutting and creates a high tension and fear for a practically unseen enemy.  The shockingly high death count in this scene contrasts with the upbeat nature of its beginning.  I found the scene quite unrealistic and something bothered me about watching it but I couldn't quite put my finger on it.  In the context of the film, it seemed to come out of nowhere with these British contractors in the desert.  Then they of course all die because this is an American film and we all know America are better than the British.  I feel the scene on a stand alone basis is good, but it really annoyed me when watching it, very long and drawn out, and pointless in a way.