I don't think war is ever "good" in reality. It may be deemed necessary, but "good"? No. War is messy and cruel. Innocent people die and often for just being at the wrong place at the wrong time.
If the historians are to be believed (and history is written by the victors) Japan was ready to fight a very long, very bloody war with women pushing baby carriages full of explosives to the beach and so on.
Which ... the reason I'm writing this is because real world war is horrible. I don't want the reality of war in my D&D game. I want truly evil enemies not child soldiers that were conscripted, "good" wars, the fantasy of being heroes without the reality. It's a game.