People seem to forget the scale of the War too. The US lost 420,000 people. England lost a bit more than that, Australia 40,000, Russia tens of millions, etc.... many being civilian draftees. The US was at War for 6 years, the others longer. Everyone was War weary.
If we were to institute Operation Downfall, the thought was 2 - 4 million injured, with 400,000 - 800,000 being fatalities just on the US side, with 25,000 - 30,000 of them in the first month.
The Japanese fatality rate would be estimated at near 10 times that.
It made sense to drop the bomb. They had ample warning with Pottsdam, they had a chance after Hiroshima. They have no one to blame but themselves.