If your point is the "rules of war" do not apply to the USA,,, But of course many radical conservatives do hold themselves above the law, common sense and decent ethical standards.
Trivial? Like you have inside information on what happened to this prisoner? Poor guy got his lip cut is all? Thats why there is an investigation, to find out what really happened. If it was as simple as you propose why would false statements need to be made? Why would the soldiers be compelled to cover up the facts? Perhaps the investigation would have found there is no need to do anything, case closed. But when an official investigation is blocked or hindered your asking for trouble.
Are these investigators, the military court, are these the "bleeding heart" liberals you speak off? I would hesitate to refer to our military officers and enlisted personel as "bleeding heart" Liberals chasing rainbows and unicorns. But feel free to call it as you see it.
The rules of war apply to all, equally. History shows a LOT of nations that ignored them, Japanese in WW2 come to mind. Many other examples. That is no reason for the USA to lower it's standards to those Nations who could care less. As Bush/Cheney did during their administration. We are better than that, have higher standards. I won't sleep with the pigs just because someone does and says it's OK.