This is beside the point. It's not that smart people aren't capable of gleefully taking part in malicious or cruel acts. They certainly are. But malicious cruel

This is beside the point. It's not that smart people aren't capable of gleefully taking part in malicious or cruel acts. They certainly are. But malicious cruelty is the byproduct of a despotic regime, rather than the underlying purpose. To a despot, power is the only goal, and everything else is just a means to an end. Sure, smart people can be complicit in cruelty. But stupid people can also be complicit in cruelty, and stupid people ask fewer questions. It's the same reason we breed dogs primarily for obedience, and only secondarily for intelligence. We have no use for working dogs that use their intelligence for any purpose other than their master's. Dogs need to be only as smart as the task requires, and the rest of the time they need to be quietly docile and stay out of the way. And there's no law of the universe that says that humans can't be subject to same pressures.