You seem to have a difficult time understanding the concept that would should elevate ourselves above the behaviors of our enemies and not sink to them. If we show the same contempt for life as communist regimes have shown, then we might as well be communists. We'd be no different.
Luckily, we have always shown a higher regard for life, and human rights and general than our enemies have. My mother worked at Camp Carson (later Fort Carson) Army Base in WWII, where we held German POW's. Did we treat captive Germans and Japanese prisoners as they treated their captives? Of course not. Had we, we'd have been no better.
Again: nothing wrong with killing communists. Having been born in a communist regime and living under it, killing Marxists is defensive in nature and is a ok.
Pinochet's behavior wasn't elevated above that of Castro? Or do you really see no difference between the death of 3,000 and the death of hundreds of thousands? Or millions?
They may have treated the German and Japanese POWs better but they STILL HAD PRISON CAMPS.
In the violent conflict between communism and the rest of the civilized world (as with Islam,) you can choose to hold to a higher standard only so long as your survival isn't at stake.
If there were bombs going off on buses and in malls all over every day, how long do you think it would take for us to set up internment camps and then begin mass deportations? It sounds like your logic would have us pretend that there isn't a problem in a society at war.
It's like saying that if I KNOW there's a guy who is raping kids and getting away with it, that I'm wrong for killing him without trial. Republican government is only so strong as the institutions and obedience to its values held by the vast majority of the people. Otherwise it's merely a vehicle for a scumbag like Hitler to take power and then begin mass genocide and wars of conquest.