Just some blind musings...
You have to consider that the world had been at war for nearly a decade (you could make an argument that it had been at war since 1914 with a pause in hostilities)
You have to consdier that between 50-100million people died. (I think the distinction between civician and military is silly when numbers are so high, everybody hopes to be a civilian again one day)
You have to consider the fact that the fire bombings imo where signficanly worse.
IMO ending this period of incredible brutality quickly and decisively was an act of mercy.
You also have to consider what happened after the war. While living through the cold war was terrifing, I truely belive nuclear weapons prevented the USA and the USSR from going to war. As a matter of fact it has prevented any two major world powers from going to war with each other. We have seen an uprecidented period of peace following the decisive end to ww2.