Since backing off the war completely wasn't a realistic option, they basically had a choice between nuking Japan until it surrenders, or prolonging the war on land and sea, and the latter was estimated to take much more lives on both sides.

I'm not saying that the US chose to go with the first option out of altruistic reasons, but dropping the atomic bombs wasn't an atrocity compared with the usual firebombing, and saved a lot of lives that would be lost if the war continued.

If they invaded the island still in war, more than 20 millions would die as they thought Hirohito was an God.

Dropping the bombs to scare the japanese empire saved tons of lifes.