Because these people are so dark triad that they're through the looking glass of being dark triad to be PROUD of being narcissist/sociopaths. They are so proud to be narcissist/sociopaths that when they feel this weird...co-NECK-shin? or...em-PA-theee? thing they hear about for some character or person, well, it is impossible for them to feel that for anyone who isn't them, personally...so they need to add sexuality traits to them until the person becomes just like them, personally, so they can feel like "oh, no. This character is like me. No, scratch that, they ARE me, personally. I'm the one having all these adventures and these other characters are my friends and I'm so cool and awesome and totally not a loser, honest."

It's honestly a level beyond this and goes to "...these people are so self-obsessed they have crossed over to become evil."