@Eerie Entity Yeah, I've thought about this a bit lately, since I started getting into these games after I found DMD. Obviously there are
truly depraved people, especially the ones who can't control the impulse and act on such fantasies, but I'm not sure we're all that bad in general. Personally, incest to me is simply a mores thing that is born of evolution or something. Our genetics know better. However, I can never get into the more intense stuff (like rape etc)... it makes me uncomfortable - I'm far too empathetic. I would assume that interest in some of the more intense stuff stems from somewhere else, like a need for control or power.
So for the example of incest (it is obvious to even plants and primates) that one shouldn't actually bear a child with someone who is a first degree relative, so if the desire truly exists, it must be rooted in something like lonliness/emptiness. If it is some kind of fantasy only, then that may be just sexuality overpowering genetics. However, this is usually from the parents perspective, as children are far less likely to grow up and still be attracted to parents/siblings due to the Westermarck effect (essentially, growing up with someone you live with causes one to be more and more disinterested in them sexually). When you start to get 4 degrees or more a part in consanguinity... it starts to be more a mores thing, where people believe it is worse than it is because we're taught it to be so. So being sexually attracted to a relative isn't abnormal, it's acting on it that is.
More extreme things, as I noted earlier, becomes something entirely different. It becomes about anger, power, sadism, entitlement, impulsive, anti-social, etc, etc... these things are in effect weaknesses of the mind, whereas the attraction I spoke of previously with relatives is more an innate mechanism. Just my thoughts on it anyways.
Edit: I don't have any kids, so I have no issue saying that the dynamic of DMD and Milfy City is attractive to me, but it isn't about the parent/child idea so much as it is the dependent/dependency, like teacher/student, mentor/mentee, etc.