I would like to propose the idea that the fans don't necessarily have to have anything to do with what the original work that started the group going. The original work could just bring together a group of people, that group of people then creates there own reasons for being together and reinterprets the original work to suit there needs. Maybe the strongest fan bases are formed around works that have a "badness" about them, because they are easier to reinterpret to suit the needs of the fans.