Sometimes I try explaining media fandom culture as follows:
Popular culture is like food. In the past, most of us cooked our own food and ate at home. We followed recipes that were handed down informally from generation to generation. Most of us could never afford to hire a chef or to go to a restaurant.
Then recipe books began to be published. Restaurants flourished. People started eating out once a year, then once month, and finally once or twice a week. Diner food arrived and with it, fast food was quick on its heels. The consumption of frozen dinners exploded. Home cooking was supplanted by prepackaged meals. We ate more and more alone, on the go, and communal family dinners fell out of favor.
Fan fiction, fan art and fan vids are like home-cooking. Commercially produced TV, books, and movies are like restaurant food. The meals prepared by fandom creators are usually based on the commercial recipes. Sometimes we follow the recipe closely. Sometimes we tweak it and add our own ingredients. Sometimes we go totally off script, especially when it becomes clear that commercial food markets have no interest in catering to our nutritional needs or dietary preferences. As fans, we still love to eat out, but mostly we love to cook for ourselves and our friends. What we cook varies in quality. Sometimes home cooked fanfiction is on par with MacDonald's and sometimes it is better than a 3 star Michelin restaurant. But that too is a matter of taste and preference.
But no one in their right minds would argue that home-cooking is illegal. That food is copyrighted and that no one should be able to replicate a recipe at home. That the only "authorized" food is the food that is produced by commercial kitchens, marketed by corporations and served up by trained chefs.
The ability to interact with popular culture - to absorb it, to reshape it, to respond to it - is a basic human need. It is as basic as eating and drinking. We have always sat around the fire telling and retelling the stories of our people. Just as we have always sat around the fire while eating the food we cooked for one another. And hopefully we always will.