It’s a fetish.
Human sexuality can be viewed as a stress-relief mechanism. Whenever events or other people apply psychological pressure to them, the conscious mind forgets but the subconscious mind holds on to it, remembers it, and tries to make sense of it.
If this sort of thing progresses far enough, and they have enough people around them validating the alternative lifestyle, the mind will start to warp the person’s reality.
I consider it a form of trauma.