Comment by peterwwillis

Nit-picking: Wars are not waged to prevent genocide. Countries are left alone to kill their own people, and afterward we may punish the perpetrators, but no action is ever taken before or during a genocide. Also, waging a war for independence is typically called an "insurgency" or "terrorism", sometimes with a more heroic title such as "revolution" or "uprising".

What's not subjective is that war is (almost) always fought for the wrong reasons. As far as ethics, "Just War" is pretty ridiculous; that the highest officials in power think it's a good idea to murder people, but only in specific ways, is just a joke.