Would you take a punch if someone you hated took two punches?
Would you go to hell if you could ensure your rivals ended up there with you?
Jesus. Who goes through life collecting people they hate this much? Maybe I've been lucky but I don't have any rivals that I'd want to see with anything more serious than a papercut or mild social embarrassment.
The sad part of the story is people often cognitive dissonance themselves about the bad they do in the world, or make it abstract because most people don't like to be the bad guy of their personal story and might score as being a fairly light person, even if they do harm.
Don't feel bad about being on the left! I would much rather have you in my life than someone on the right (unless perhaps we're in a war or something).
“If you know the enemy and know yourself, you need not fear the result of a hundred battles. If you know yourself but not the enemy, for every victory gained you will also suffer a defeat. If you know neither the enemy nor yourself, you will succumb in every battle.”
- Sun Tzu, The Art of War
The "darkness" metric is meant to sample the traits that, in high quantities, make for some pretty pathologic - sometimes criminal - disorders.