Earlier quoted context omitted.
yet the world did not end. Countless prophecies aboutvthe absolute apocalypse have gone and passed. So yeah it is by large irrelevant.
It's not a given that it did not end... think to yourself what would happen if Nazi Germany had developed a nuclear bomb ahead of the Americans? If even the US government couldn't resist obliterating 2 cities in Japan with Nukes can you imagine what the Nazis would have done? There would have been zero consideration for the loss of human life, possibly large areas of continental Europe and the US would have been bomb…
Nukes at the time were still weak weapons. You could inflict a lot more damage (and a lot more damage happened on Tokyo and many other Japanese cities) by regular firebombing. You did not need nuclear bombs to inflict catastrophic loss of life.
Now when it came to thermonuclear weapons, the magnitude is entirely different, but that only occurred many years later. It would never have occurred at the time of WW2.