The other choices were to starve Japan into submission, or invade.
Both would have resulted in much higher causalities.
I get into this argument on the Religion Forum all the time. Japan in WWII was evil. They did some rather horrific things to the territories they conquered.
When you start wars, expect blow back. Something the US needs to acknowledge as well.
It seems there are a few points of comparison between Japan in WWII and earlier years and a certain culture today. Namely Japan had an intertwined religion and ruling culture with horrible racism towards the rest of Asia and the West. The Chinese and other Asians were not considered real humans.
Sound familiar to anyone today?