I think you are confusing two things, sparkie.
There's the snap decision that you have to make "when a big 'airy Russian comes at you, with a gun in one 'and and an 'alf-eaten baby in the other" as a small arms instructor once expressed it to young Darth while at RMAS. That's when the RoE may get a little stretched, and frankly that's probably OK to err on the side of caution and shoot the bugger, unless of course the bugger is driving an Italian journalist.
But once you've captured them, there are certain expectations, and you can't really talk about the "heat of the moment" unless there's an escape attempt or some other mayhem going on. Beating the crap out of helpless prisoners is ineffective as an interrogation technique, and is morally wrong.
It's not a matter of shedding a tear for the poor prisoner. It is a matter of allowing even those we are fighting the appropriate due process. One of the things that is being lost right now with all the Spam-inspired terror-hysteria is the concept of due process, and the inescapable fact that some/maybe many of those incarcerated in these camps may well be moderately innocent.
Especially in conflict in built up areas (or whatever the current jargon is for house-to-house fighting where you're not sure who might be against you), there's a tendency to sweep up everybody and his dog and throw 'em in the pokey. That works quite well, as long as you have some way of processing out the ones who are not of interest. Over here in the US, there is a tacit (and in some cases explicit) assumption that anyone who has been picked up by the forces of might, right and justice is guilty of something. And any suggestion to the contrary is "supporting terrorism" or "disrespecting the troops" or "being anti-American."
But from Magna Carta onward, including such things as habeus corpus and the Hague and Geneva Conventions, the correct and useful treatment and interrogation and (in some cases) release of prisoners has been hammered out. And to step back from that is disgusting. I'd like to think we are better than that.
(noted on preview): So in Interrogation training, how many of you were killed and maimed by your interrogators?