Again, Camp David, I'm sorry to disagree, but I believe you're completely wrong on this.
Think about this. You're brought up as an American, believing in our system of laws, rights, values, etc. You enter our armed forces, voluntarily, to defend your country and what you believe in. You're then told to act in a way that completely ignores all those laws, rights and values in which you believe, and are furthermore told that this is justified because those upon whom you're inflicting torture are "not us" - that makes it OK.
Sorry, but this is a moral disconnect that's simply impossible. What's to stop that serviceman coming back and doing the same things to other Americans? After all, we've taught him that it's OK under certain circumstances - so what's to prevent him redefining the circumstances, to decide for himself when it's OK and when it's not?
If something is wrong, it's universally wrong - otherwise it's not "wrong" as such, but dependent upon circumstances. The same goes for something that's "right". If it's not a universal condition, it can't form part of a moral or ethical code of conduct, as no law or rule of behavior can be made conditional upon it. To say that torture is OK under certain circumstances, or against certain individuals, begs the question of precisely who defines the circumstances or selects the individuals, and what criteria are used in the definition and/or selection. If someone can designate a given circumstance or individual today, someone else can designate a different circumstance or individual tomorrow, and all pretence at a rule of law or a Constitutional mandate is lost - there is no longer an absolute authority. (And note that this completely ignores questions of religious morality - that's a whole other field, which is too explosive for this thread and this forum.)
We cannot claim to be a moral and/or ethical society if we make morality and/or ethics subject to circumstances. They either apply universally, or they're not moral or ethical standards at all - just opinions.
Oh, by the way -
you misunderstand the role of a soldier... soldiers are trained to win wars, not accept Monday Morning quarterbacking from back on the home front.
I served for four years in another country's armed forces, and saw combat on a number of occasions. I also underwent officer's training, and understand from both the "grunt" and leadership perspectives exactly what is "the role of a soldier". Soldiers are not only trained to win wars, but to do so under a system of military discipline that embodies the Constitutional approach of their country. Once they depart from this framework, they become "loose cannons", and end up doing far more damage to their own country and society than they do to the enemy.