Why do humans believe it is ok to treat other people as less than important because of their status? (Night Book)

This is obviously a tremendously deep and difficult question, but at least one good reason for this all-too-common phenomenon in human affairs is fear. Fear is a universal problem that plagues humanity as a whole, and it reveals itself in various ways. The fantasy of security in status (and the elimination or subjugation of others) is a classic antidote to this deep fear.