While I respect that other Authors are entitled to their own thoughts and opinions about Fan Fiction regarding their own stories; I get the feeling that some of them don’t understand that when people write Fan Fiction about their work, it means that it has been so impactful that their fans want more... so much so that they MAKE the more themselves. The More that they know will never be written, or explored. Or they want to see some of their other Fandoms mixed together in a big wacky crossover where the characters interact and fight (side by side or with each other) and so on.
I also think there’s a lack in understanding of what Fan Fiction actually means to the readers and the writers. It’s an extension of the original works, an exploration, a 'What If' factory of unending ideas, its a school for writers to hone their craft, a place where a reader can find their favourite character ships explored while the Author will never do that. Not to mention the fact that underrepresented people, like; Gender, Racial groups, the LGBTI+ community, Disabilities, Inter-sectional, etc, are being represented in more accurate proportions in this format than anywhere else.
While the intellectual property, and the profits of it, should always belong to the Author, this does bring up the debate of whether art is truly yours anymore once you give it to the world, or if the art itself becomes something more due to people's personal interpretations and ideas about the work. For instance, an Author can’t possibly go around to each person and correct their perception of their work, “No no no! you must read it as THIS not THAT! You’re reading it wrong!”
Honestly, so long as it’s not plagiarism or written for profit, I look forward to reading the fanfiction written about Once Upon A ...What? I think it would make me a better writer. People coming at my work from angles I might not have thought about, people exploring their theories and ideas about certain scenes, etc. I think it would be fun to see the people I've created having adventures with Captain America or Harry Potter. I can't wait to see who ships who!