The problem is most of these subhuman screaming banshee lead-poisoned troglodytes have worked in customer service or actively do.

The issue is the people who treat customer service like shit treat almost everyone like shit and have no ability to develop self awareness.

These people operate with some form of deep social disorder (like narcissism for example), and think they themselves are incapable of wrong doing.

You cannot help these people. You can only respond with equal or greater aggression and socially isolate them, which is exactly what they deserve.