He advocated an immediate preemptive nuclear strike on the USSR: "If you say why not bomb them tomorrow, I say why not today? If you say today at five o'clock, I say why not one o'clock?"
This is why he was dismissed in so far as foreign policy was concerned, where nuance and patience takes precedence over cold, calculating game theory. Not only would it not have been feasible (Russia is huge), but it would have led to follow on effects by possibly pulling the US into potentially another world war. This is evidence you can be a genius in some areas and wrong in others.
That quote doesn't sound like advocacy of an immediate strike to me. That "if" is massive, and going into the details of why you're not already attacking is very likely to give you reasons that keep making you not attack.
Maybe there's some context that suggests otherwise?