We're Americans. We're supposed to be the good guys. Part of our strength is our capacity to be humane. While our nation has mastered the art of the big stick, it has forgotten the part about speaking softly.
Towards the end of World War II, Germans fled west towards the Americans and British to surrender while putting up a stiff resistance against the Soviets. This is because they expected better treatment from the western Allies. If Taliban holdouts expect to be subject to torture or "advanced interrogation techniques" (or whatever euphemism you prefer) when captured, that makes it much more likely that they will fight instead of surrender when cornered, thus increasing the possibility of American casualties.