Except, well, the Taguba reported clearly stated that somewhere around 60% of the detainees were innocent of any crime and where of no threat to the US.
With all due respect, this is not about what you deem to be acceptable, for your own troops or anyone else. The fact is, there are long standing international laws regarding the treatment of POWs. Its not up to the troops, or even the commanders to make it up on the spot.
Also, you do realize that your situation is hypothetical only, right? US troops get more or less carte blanche. Even the most serious of crimes are excused by the Army, or given minimal reprimand. Now, assuming that someone ****s up bad enough to deserve serious punishment, and that the Army is powerless to protect him/her in the face of astounding evidence, they wouldn't be tortured. At worst, they spend the rest of their lives looking at the inside of a miliotary brig, but no way would any soldier ever treat his own the same way as an Iraqi prisoner.