Not to minimize the horror of the weapons, but Hiroshima and Nagasaki were legitimate targets as they were large Army barracks at the time. It's just like Dyess is a legimate military target today, and the presence of Abilene is irrelevant. Also Nagasaki wasn't even the primary target - Kokura and its steelworks was, but smoke from a previous bombing run against a neighboring city made it impossible to hit the target.

War is hell, pure and simple.