Let me be blunt: what you believe isn't relevant. It happened the way it did and what the other leg of that choice contains is something that nobody knows and therefore debating it is pointless.

What we do know is that a great crime was committed, the balance of which is also irrelevant, because whether one, ten, ten thousand or 100,000 or even millions of Japanese lives would been saved we do not know. But we do know how many were lost.