Look at the BS charges that soldiers have been slapped with since we went to war with the Islamofacists. Why wouldn't they lie about roughing the guy up?
We're not even sure the guy got roughed up. He may have struggled upon capture and sustained those injuries, making them accidental. So, these men may not even be lieing, to begin with. BUT, some folks on the other side of the political fence aren't going to give these soldiers the benefit of the doubt and we all know that.