I wonder if it has as much to do with the forbidden-ness (is that a word?) of it as it has to do with everything else?
I mean however you say it there are only a handful of humans who would nod and smile if you told them you enjoyed drinking blood. Most of them would just think you were creepy, and some would think you were deranged and dangerous.
Maybe part of the attraction is the creepy and dangerous image it has.
I'm not exactly sure what you mean by 'humans natural enemies' Sephunveyna, but I don't think I have any of those.
As an essence, all I exist with are like me and no-one like me is my enemy, they are my Kin. Until they give me a reason to think differently.
When I'm in a human body I don't think of other humans as enemies unless they start it, then I stand up for myself, but then I always stand up for myself when I'm attacked, no matter who is doing the attacking.
When I am Dragon I don't have any natural enemies, only prey.