How is nuking some other country a better future. How are you going to argue for that I wonder. You're going to cause millions of deaths even without retaliation. How are you going to justify that, simply because "they're not us"?
While it's easy to dismiss that view in hindsight, it's worth considering that von Neumann had personally witnessed the rise of the Nazis and had to flee along with many of his friends and family. And he had seen that regime defeated only by military strength of the USA. And while the USSR and USA never did end up in a nuclear war, it really was only by a series of miracles that it was avoided. I think most historians of the 20th century would agree we got very, very lucky.
https://en.wikipedia.org/wiki/Hungary_between_the_World_Wars