Why can't people let go of their mechanical and inconsiderate attitudes?

Throughout their lives, I know there are plenty of terrible people who live within hierarchical relationships—thinking "I am the superior and you are the subordinate"—and can never shake off their mechanical and inconsiderate attitudes. Please tell me why there are so many of these malicious people.
Because while they should know how to show understanding when it's necessary, they live their lives scoring zero on every single thing from A to Z.