It'll make them even more anti-social, because now they have a human simulacra they can mistreat at will and still never get the validation of human companionship.

Having slaves is not good for the slaver's psyche. It makes you a bad person. Even if the robot is not human, if its made in our image, if its meant to replace a human, then treating it like a slave makes you accustomed to treating other humans like slaves.