If you think that "modern society" is that evolved, you're very fortunate that we haven't had anything near total war in 68 years. Morals quickly fall by the wayside when a country's way of life or existence is threatened. Read up on SIOP and the Soviet equivalent, and you'll see that we trained thousands to use nuclear weapons, spent trillions, and the Soviets did as well. The gloss of civilization is a thin veneer that can easily be degraded.