And irrationality doesn’t correlate with stupid in any meaningful way as people can be intelligent up to the point where some dogmatic instinctive belief means that their raw unfiltered emotions suddenly guides their decision process.
And lets be honest most actual genocides are committed by smart(often very moral) people acting on irrational fears or dreams of an utopian future that can only happen after the world is purified of some specific evil.
Selfish bastards aren't nearly as dangerous and fanatical zealots chasing some utopian dream but being fanatical don't mean your ignorant just that at one point your emotions take over from logical reasoning.