But if there is no fight occurring, and the enemy is subdued and unable to cause harm, then the situation has changed a bit, into a greyer area.
I've also met a guy who has used water-boarding in the field, and he didn't seem like a sadist. He felt pretty bad about using it, though he thought it effective and necessary.
If you make an effort to reduce suffering it comes as a complete package: people quick to torture are the same people who would use Sarin on civilians. There is simply no middle ground. The concept of innocence doesn't come into play anyway. Wars are mass murders stemming from greater social and political processes; a conscript soldier guarding a fuel depot is not any more "guilty" apriori than his civilian relative.
There is more or less intellectual consensus that wars cause suffering, and attempts are made to reduce the misery. Propagating torture is not serving a good cause here. You essentially argue that a "lesser" crime is acceptable in context of a "greater" crime going on anyway. If one's going to kill the victim might rape her anyway.
Note that I am not taking any pro or contra torture position. I'm merely pointing out the moral inconsistency.
For you and me yes. For people who believe targets are "bad people" worth killing it's noble intent.
In case of torture you can't claim that individual you torture is somehow accidentally hurt. Probsbly those people would be fine with torture if they thought hurting the tortured individual is desired outcome.
The incompetence of humans to intuitively make moral judgements is precisely why we should think rationally about morality rather than emotionally.