In a sense, I think they are right. My guess is that this is not such an isolated incident. Also, I think that this incident has been "encouraged" from higher ups in both the military and intelligence. Check out this article from late 2002:

http://www.iht.com/articles/81546.html

If senior military and intelligence people are saying things like this in 2002, is it really any wonder that the enlisted grunts have come to do what was done at Abu Ghraib?