What? Hitler didn't have a high IQ, that shit's a myth. Hannah Arendt debunked that way of thinking in
Eichmann in Jerusalem. (I've encountered many people over the years who've said shit like: "If the Jews are so smart, how come they couldn't stop the Nazis from almost exterminating them?", implying that intelligence and power match up in the real world. Well, they don't always. Of course, it's true that highly intelligent people have also been violent sociopaths: Ted Kaczynski is a better example of this.)
As for what I said, I didn't mean "screen em for mental illness and toss the ones we think are sociopaths in prison then." I meant that we should pay more attention to the mental state of children, because sociopathy does manifest in childhood (the Virginia Tech killing could've been prevented, for example). It's a two-fold recommendation: on the one hand, emphasize a culture of care (involving an understanding of common interest and social values and so on); on the other, recognize those who are unlucky enough to have mitigating physical factors that need to be caught early so that they might be able to lead a normal life and not endanger others later on. It's not an exact science, of course, but we're at a point where we could be doing more. It's not like I'm advocating prosecuting pre-crime.