Ok then. Tell me what you would have done. Japan was beaten militarily and economically, this is true. But their morale most certainly was not beaten. When they realized that their air force was no match for us, they started purposely flying their planes into ships - surely you heard of the kamikazes. They were as fanatical an enemy as you could have imgained and viewed their emperor as a god. The only way they would have stopped fighting was if their god/emperor would have told them to - and the only way to do that was to show him just what kind of destruction we could bring down. Remember, we warned the emperor what would happen if he didn't do the sane thing and accept defeat, he didn't listen.
So the choice was end the war with bloodshed quickly, or end the war with even more bloodshed slowly.
"To avert a vast, indefinite butchery [the invasion], to bring the war to an end, give peace to the world, to lay healing hands upon its tortured peoples … at the cost of a few explosions, seemed after all our toils and perils, a miracle of deliverance."
There's always one thing that confuses the hell out of me when it comes to this subject. How can you argue on one hand that the Japanese citizenry in 1945 would be so fanatical and zealous in the defense of their country that they would have all fought to the death against invading U.S. forces, then turn around and acknowledge that they were so docile that they willingly accepted a total, humiliating surrender at the behest of an old emperor who they probably never saw in their lives?