Many of the "social justice" crowd get off on the moral superiority they feel from engaging in rabid political correctness.
Unfortunately for them, moral superiority is by definition a positional good, a good whose value rapidly diminishes as PC concepts become increasingly mainstream. Thus they seek increasingly extreme levels of political correctness to signal their status as being above the common rabble.
Unfortunately for them, moral superiority is by definition a positional good, a good whose value rapidly diminishes as PC concepts become increasingly mainstream. Thus they seek increasingly extreme levels of political correctness to signal their status as being above the common rabble.