My raidteam managed to get a server first boss kill while raiding Mythic Tomb of Sargeras in World of Warcraft:Legion. I was so proud of our teams achievement, I actually got a tattoo of the Mark of the Kirin Tor, a symbol for my mage character, in commemoration of the achievement.
It’s only okay when the alternative is “your entire population is killed.” If you’re not fighting a defensive war with high stakes, then it’s just a way to kill poor people and political dissidents.