No, you don't know that the reality will be different. This is something that has never happened before, and only a certifiably insane person would try and downplay the horror of a nuclear war.

Did you not see what happened to Russia’s latest Satan II ICBM? Thankfully that one wasn’t armed.

Do you know how many missiles Russia has, even if a tenth of them go off we're all fucked. And frankly, people who don't care about dying can just kill themselves any time they want. What fucking right do you have to gamble with billions of lives of other people?