Is that also true on AtS (which I haven't seen)? I'm not sure, I haven't seen a ton of AtS episodes.

I assume there's some silliness behind that, "Vampires are amoral and don't care about the usual human rules of behavior - ergo, they feel free to wear eyeliner! EVIL!" I always assumed that it was a make up choice, decided by the higher ups to drive home the point that they were evil. Kind of like the bad guys wearing black hats.