My uncle Denver Miller was also on the Atlanta (sister ship) in the same battle. His whole gun crew was wiped out from a direct hit, Denver was the only survivor and spent 2 weeks on Okinawa in care of the Marines until he could be transported to Pearl Harbor. The Atlanta was so damaged that it was scuttled the next day.
Ordinary men became extraordinary heroes in an instant. God Bless them, and their sacrifices, to a man.
When we know, first hand what these men endured, there is no question, that Truman did the right thing, dropping the bomb.