Punching down. It’s often why bullies are bullies, they are someone’s victim and the lesson they learn is to find someone weaker to make a victim.
If you tell someone they are less than and they believe it, they will start looking for someone less than themselves to treat the same way.
It’s inferiority from the top down. Trump talks in terms of being the best, the greatest, etc to mask his true feelings. He feels he is less than. Maybe not consciously, but it’s absolutely something that weighs on him.