Creatures reproduce according to their kind- just like the Bible says, actually. Parrots are attracted to and mate with parrots. Mice are attracted to and mate with other mice. Frogs, well, you get the idea. Humans have a biological compulsion to reproduce due to certain hormones, and if the glands driving these compulsions are removed (castration), so is the desire to copulate. So why would a demon, a being created without gender and the ability, let alone the desire, to copulate seek out "attractive" human women to have sex with? It would be like a human looking at a piece of fungus and wanting to secrete spores; like wanting to undergo mitosis and watching some paramicium pornography. LIke a human being seeing the red feathery crest on some species of finch in South America that make the other finches want to mate, and becoming aroused. There's no logic behind a demon wnating to have sex with a human being.