'Dark' people don't hide it as well as they'd like. When it becomes clear somebody wants to play the dark game, all the choices become restrictive. Someone who has gained a position of authority with those traits is usually not worth challenging because you have to play the influence game in the dark where the rules have likely been implicitly set up against you. Inspiring fear or exhaustion becomes easy.

Light people can choose to play this game, and they can choose to expand into a different space. There's somewhere else to shine your light and it's usually more saistfying to expand elsewhere joyously than influence in the dark with fear.

If 'dark' people display their traits and abilities, it's no longer dark. Immoral choices tend to reduce your options, not give you more.