Yes, let us preemptively kill millions of people just because someone is saying exactly the same sort of thing they've been saying for the last 30 years.

Iran's rhetoric is nothing new. They aren't actually irrational, they just like to saber rattle from time to time. It's as much for internal political reasons as anything else, often more for that reason. But they won't attack Israel because they know that if they do they really will get nuked.