I never mentioned the Cuban Missile Crisis. You’ve misinterpreted what I said.
The USSR getting nukes in the first place lead to several incidents which were a judgment call away from armageddon. With the benefit of hindsight the correct call would have been to exhaust all options to prevent the soviets from acquiring nukes.
We just got lucky. Whether it was the Cuban Missile Crisis, the soviet early warning system malfunction in Sept 83, or Able Archer 83 in November, there was a lot of dumb luck.
Proliferation will bring the end of humanity. There will be too many actors, too many variables. You can get lucky with 2 actors. You can’t keep getting lucky. The only option is to ensure you don’t have to be lucky.
I assumed you meant the Cuban missile crisis since that is the only tenuous connection that can be made between "USSR acquiring nuclear weapons" and "end of humanity". If you generally meant "any nation acquiring nuclear weapons" then the statement would kind of make sense, but there is no reason to fear just the USSR, and not, say, the US, China, India, Israel, Pakistan, or North Korea. Maybe some information made it into the popular press about the USSR, but it is unlikely that there is something especially dangerous about the USSR compared to all these other nations.
And in any case, the genie is out of the bottle. There is not gonna be a situation in which a small group of nuclear powers endlessly bomb and attack other countries with impunity. The other nations will get nukes to defend themselves against the existing nuclear powers, it's just a matter of time.