I personally believe there is no way for them to succeed. If they were acting in good faith the actual incease in the number of intelligent people, who would recognize cruelty when they see it, would tear it down. If they acted in bad faith, which they most definitely would, they would fill the world with these idiots.
Societies have 100% operated under other moral structures. Under the moral operative that human life is inherently valuable our society has progressed further then any other recorded civilization.