This is an interpretation of what happened. It's the one that paints America in the most favourable light, for sure.

Another one is that the "no surrender" mentality was a direct result of the terms of the Potsdam Declaration which demanded "unconditional surrender" from Japan. Japan knew they had lost, they were just hoping to fight for the SPECIFIC surrender condition of the preservation of the Imperial line (aka, let the Emporer still be the Emporer, preserve the family).

Had the Potsdam Declaration permitted that concession, it very well may have been the case that no nukes would have been necessary.

Anyways: tough to understand the exact truth of any hypothetical situation. I just think it's unfortunate that the "The USA HAD to, though" argument is so often repeated without a very full context of the surrounding political realities. It's a very bite sized explanation, and it paints the USA in a fantastic light. It's perhaps not a coincidence that it was AT Potsdam that the west hinted to Stalin of the existence of the nuclear bomb.

What's the point of building the thing if you can't prove to the world you have it, and are willing to use it?