They dropped two nuclear bombs on Japan to make the Soviet Union's invasion of Hokkaido unnecessary and as a performative act to horrify the world in to subjugation.
The whole 'saved more lives than it cost' is a bad argument unless the plan was to slaughter a hundred thousand civilians on landing. Note the Nazi invasion of France cost 60,000 lives in civilian resistance...this was at the beginning of the war.
Japan would have surrendered on the first day of invasion.
the ija and ijn deserved to be nuked but amerikkka just had to nuke civilians instead and let those war criminals takeover our post-war government instead :angery:
Amerikkka was totally fine with those fascists stepping on your dicks, until their empire crossed ours.