We can't have their covers blown. After all, then we would have some idea who should be punished for "just following orders." (By the way, don't you like that term, "waterboarding"? I can't get it out of my head that before the interrogators begin, they holler, "SURF'S UP!!!")
In fairness, we really should consider the argument that those who were on the receiving end of the abuse possessed information vital to the protection of the United States. Still, shouldn't we always remember what it is about the United States that we're protecting?