Okay, some fandom history, why show writers and authors say “for legal reasons” the can’t read fan fic.
Back in ancient times in the 1970s there was a show called Star Trek the Animated Series. It was on the air as fandom culture around Star Trek was really taking route and there were many fanzines (things on actual paper that people bought) being published and the first conventions to attend.
David Gerrold was a writer for Star Trek the Animated Series who had also written one of the most famous episodes of the original series The Trouble with Tribbles. While he was around the production office for STtAS he was introduced to a couple of fans who proceeded to tell him all about their ideas for an episode–essentially a sequel to his famous episode–which it so happens he had already written a script for. When that episode aired he received a letter from one of those fans lawyers demanding “credit”. It so happened that he could prove that the episode existed before the meeting but the involvement of lawyers and a threat to sue became widely known.
Marion Zimmer Bradly was, before recent horrifying revelations decades after her death, a titan of fantasy writing. She also welcome fan fiction and published it in anthologies and in a magazine she published. One day she opened a story sent to her and the plot of the story was essentially the plot of a a novel she had nearly finished writing. More than a years worth of her work was now unpublishable because it was provable that she had read this story with this similar plot and she couldn’t prove the work on the novel existed before she saw the story. She stopped publishing anthologies and fan fiction and in particular the MZB story is the one a lot of professional writers know as representative of the dangers of fan fiction.
So when a writer says they can’t read fan fiction for legal reasons it’s that their own lawyers are protecting them from outside lawsuits.
And this is why knowing your fandom history matters.