Who Runs the (Fictional) World?

Nobody loves lore more than me. As ashamed as I am to admit it, I've spent many a night spiraling down a GameTheory rabbit hole learning all about worlds and histories of video games I've never played. I've probably sunk the most amount of time into Five Nights at Freddy's theory, which is built solely on the contents of six games (and three books that most would like to forget exist). The detail and tiny hints built into the gameplay build up a whole universe with plots and secrets deeper than the surface game, and honestly, I find that incredibly impressive and entertaining. It's like solving a murder mystery (without the murder, hopefully) except the clues lead farther into the creator's mind where all the secrets are kept. Anyone can throw some plot points together, but storytelling like this is often hard to find.

But I digress.

What I'm really here to ask is who decides what is included in the lore and what isn't. Believe me, I am all for more backstory, but only if it's genuine. My main issue is with authors like JK Rowling, who add to their worlds whenever they please.

I used to love learning more about Hogwarts and her secrets through Pottermore and JK Rowling's tweets. It was super cool to think that there was all of this lore in her mind that she now finally had the chance to share, but eventually, I had to wonder what had been planned with the rest of the books and what is being made up as needed. One example of this has pushed the issue into the spotlight on the internet, a passage on Pottermore (seen above) claimed that instead of using muggle toilet technology, wizards would just...you know... pee themselves and get rid of it with magic. To me, this was clearly made up on the fly. Seven books prove that Rowling is much more creative than this and is great at writing long fictional histories, and this piece of lore doesn't fit that. I'd expect something from her to be more planned out, or at least make more sense, which makes me think that this was a hasty creation.

In this example, Rowling's new addition doesn't fit with the existing lore. In Harry Potter and the Chamber of Secrets, we learn that Hagrid was raising a giant spider while a student at Hogwarts, one that eventually ends up living in the forbidden forest. We know Dumbledore doesn't try to put this "foolish acquisition" back; Aragog spent his whole life in the forest and had about a gazillion kids. Am I supposed to believe Dumbledore didn't know about that?

I'd love to believe this one, but there's no evidence at all in the books that this would be true. Feels like something added after the fact to me.

See what I mean? It's hard to discern what is part of the original plan and what isn't, which begs the question, who gets to decide what gets to join the lore and what doesn't? How much are authors allowed to add after the fact, and do they carry the same weight as what has been written? Am I overthinking this? Probably.

TLDR; I'm down for more of the fictional universes, but please, authors, be careful with them! Please don't ruin what we've already fallen in love with, and if you have to make changes, please put time and effort into them so that they fit in seamlessly with what you've already written.

Thanks xx