I’ll go with the opinions of the Americans who were lined up to take part in the invasion of Japan. I never knew of one who didn’t believe that the dropping of the bombs probably saved their lives.
I was one of those actually lined up for the invasion of Japan on August 15. All in the line up were glad for the news. I was of a somewhat bit different attitude as my brother had been killed on Okinawa in April and I was still filled with revenge. Personal fighting in a war is hell and revenge and I can honestly say my training for such especially after the death of my brother took a while to overcome as morbid and foolish as it might seem to those without the experience. Truman was more of a civilian soldier than the professionals who are given civilians to be their pawns for their games. I believe the Japs intended for the USA to suffer heavy casualties during the landings so they could bargain for a deal benefiting them.