George S. Ledyard
Actually, the guys I have always found interesting are the Chaplains in he military. Clearly, their religious faith calls for not killing people yet they have historically been a part of keeping the troops in line and functioning. I find it fascinating that they can justify this and square it with their faith. Thou shalt not kill being fairly clear, I think.
That's the thing with rationalizations, justifications, and excuses. The sole purpose is to prevent you from being accountable for what you are ACTUALLY doing. My grandpa stabbed some German boys in the throat with a bayonet in WWII, presumably in the name of defending freedom. Nobody gave him a hard time about it, but it was something he personally couldn't forgive himself for. The samaurai kills as an act of loyalty to his Lord, presumably in the name of duty and honor; or in the case of ronin, simply as a means to earn a stipend. To them, they are perfectly content with the atrocities they committed, even when their victims and onlookers view them as cold-blooded murderers. Is this moral relativity? Yes, it certainly is.
The moment you allow the possibility for someone to excuse or justify an act of killing, words and actions will be twisted and bent to serve individual needs. You are right George. Peace (i.e. nonviolence) is a crystal clear principle.