All human beings personify humanness, for good or ill.
Each is a discrete unit of humanity in action. Each of us portrays the various traits and states found in humans. Whether or not they are shared with others in the animal kingdom.
When you decide some or other person or group is intrinsically degenerate or pathological, it changes the way you view not only them, but the quality of being human itself. You will see things about yourself in them and not recognize them as that. And vice versa, because the cutting of your shared state makes you strangers.
You will see things that are not like you in them and think, that signals their pathology, rather than just difference.
This means you begin to undermine your understanding of the species of which you are part. You therefore begin to unravel your understanding of yourself and the science of human beings.