That's just silly if I don't like a genre I just don't watch anime that have ingredients of it. Incest especially isn't a genre, it's a niche part of certain Ecchi and Hentai anime, and very rarely proper romance anime.
This is a bad way of looking at it though because the type of media they consume isn't the root cause it is the illness and abuse and with out this they would not be influenced in the rare cases they are to do these things.