Probably because all Arab countries treat their prisoners in the same way and because human life is worthless to them compared to the prophet's honor, but it's still no excuse for a western country to do the same, those pictures could have been taken in a concentration camp of the 3rd Reich or a gulag of the Soviet Union, and it's appalling that the US isn't treating its prisoners better than those totalitarian states.
Also interesting is the fact that those pictures are banned in the US and that Americans are probably the only people in the world who have not seen them, the only thing that seems to interest American media at the moment is Dick Cheney's hunting accident, yeah…