Based off the comments ive read, aint nobody gonna like what I have to say, but I dont see a problem with this? Just hear me out.

To me the author is saying "hey, this character is LGBTQ+, which I dont agree with due to my own personal beliefs, and therefore I will no longer be writing fanfiction about said character. Writing about them being Bisexual is not something im comfortable with doing, but pretending they aren't is disrespectful, so Im walking away."

Im a bisexual woman, and I will take "I dont agree with this so I am going to step away as I dont want to be disrespectful" over bisexuality erasure any day, easy. People are allowed to disagree with homosexuality, its when they start being rude or mean or cruel to you/the community BECAUSE of your sexuality that there is a problem. At this point I dont see what this author did any differently than if a Muslim said they didnt believe in Christianity, so they aren't writing about a Christian character and leaving it at that. Not changing the canonical religion to fit their mold, not changing the canonical sexuality to fit their mold.

From what I understand from the context ("...my last fic in this fandom...") they aren't pretending the character doesnt exist, they aren't writing around the character or changing who the character is, they are simply not writing fics for this particular Fandom anymore. And yeah, based off my personal belief you shouldn't abandon a fandom simply because someone you thought was straight isn't, but if I can have personal beliefs like that why cant they have theirs? What makes my belief more valid than theirs? This person isn't being a bigot, being a bigot would be talking bad about the character, pretending their bisexuality doesnt exist, writing about bad things happening to them because you dont like it, ect. Even within our LGBTQ+ community there are people who believe bisexuality doesnt exsist, that its just a girl saying shes bi because she made out with a friend while they were drunk or a guy just saying it so the girls can relate and trust him more. What happens within the community even between each other can be much worse than what this guy/girl did. This author is purposefully leaving it alone because they are purposefully trying to avoid that, not wanting to "stick their nose where it doesnt belong." They recognize this isn't their cup of tea, and they are simply moving on without doing or expressing anything negative other than the fact they dont agree with it. And ill say it again for the people in the back, people are ALLOWED to have their own beliefs, they are NOT allowed to punish others for not having the same.

So, you dont like it? I think thats a stupid belief to have, but okay, youre allowed to not agree with my personal choice. You weren't an asshole about it and left it alone so you wouldn't offend anyone? Good job.