It was a different time. The casualty
estimate in US lives was somewhere between 500,000 and 1,000,000 lives to invade Japan.
I was in kindergarten in 1970, and I remember some researchers coming into our classroom, and they tried to explain to us that that Truman had a difficult choice to make. Do you take X amount of Japanese lives? or Y amount of American lives. Does the decision change if X is > or < Y? What if some are your relatives? Which do you choose?
Apparently it made an impression on me, as I remember it to this day.
I had a great uncle who was in both Iwo Jima and Okinawa, and I'm guessing if they had invaded Japan, he would have been one of the 500,000 to 1,000,000.