ROK Counter-Guerrilla doctrine was shaped strongly bu the recent fighting they had done in their own country. Few people realize that while all the more commonly discussed fighting was going on up to the Yalu, and back, and along what was to become the DMZ, ROK soldiers were fighting continuosly in the rear areas with insurgents who used tactics almost identical to those later used by the VC. The ROK Army learned some tough lessons about fighting such an enemy - which often included the necessity of killing or torturing their "own" people.
The best explanation to understand the mindset of fanatical guerrilas is the "horror" speach by the Colonel in "Apocolypse Now." ROK soliders understood that those were the techniques of their enemy, they were more than willing to fight fire with fire, and had no qualms about creating civilian casualties to support the greater goal.
The VC were willing to use the most heinous threats of torture and murder to force compliance by neutral villagers. We Americans could not compete with that kind of pressure, short of eliminating all of the VC and then convincing the locals that was indeed the case (similar to the struggle in our cuurent operating environment). In the case of the ROKs, the villagers feered them more than they feared the VC.
American sensibilities simply cannot tolerate the tactics that work and are a fact of life in most of the third world. Heck, most Americans are in denial that even people like Hussein could be as dastardly as they are. I have my doubts that the ROK Army circa 2003 is anything like the ROK Army circa 1966 - their society now is much more softened and liberalized - and is amazingly like ours was in the 1960s.