Stigma - Chapter 41

I guess Michael had a troubled past and as a kid, was neglected by his mother. Desperate for attention, he constantly sought his mother's approval. Also he had low self-esteem, so he compensated by exerting power over Sehyun, a behavior that momentarily boosted his fragile ego. Also, he projected his own insecurities onto Sehyun, labeling himself as "different" and Sehyun as "worthless" in an attempt to validate his own sense of self-worth. This proves how bad parenting can turn you into a monster.
But again this doesn't justify his actions. He's the real piece of sh**.