Some people act WAY too entitled when it comes to fandom, in a way they probably wouldn’t in other hobby spaces. If they went to, say, their local fibercrafts club meeting* they might see how rude their behavior really is.
The way they treat people 30+ in fandom spaces? “Young people don’t belong in the knitting club! Don’t they know this is only for people with grandkids? They should go do their homework or something! I don’t care if the craft will die without new people learning it.”
The way they give unrequested criticism? “Give me your needles, I’ll show you how to do that stitch. I don’t care if you thought it was fine, or if you wanted to learn to fix it yourself. I’m fixing it because you’re not good enough.”
The way they react to anything that they think is out of character, or goes against popular fanon? “You can’t modify the manufacturer’s pattern! There’s only one right way to make this, and you’re screwing it up! I don’t care if you like he way yours turned out better!”
The way they act about adult content? “That crochet bikini is too revealing, I wouldn’t want to wear something like that! You need to give it more coverage to make it something I would wear!” Or “You can’t cross stitch swear words on your pillow! I don’t care if you’re keeping it at home and only showing your adult friends! What if a child wanders into your living room and reads it, then starts repeating those words?” Or “You can’t call you crochet group the Happy Hookers Club!”
The way they act about there being lots of fic for ships they don’t like, and not much for those they do? “Blue is so mainstream, blue sweater enjoyers are privileged. I don’t care if blue is your favorite color, if you were an ally, you’d knit a green sweater! I don’t care if everyone outside this club thinks all knit sweaters are out of fashion, including the blue ones.”
When you think of a finished fic or piece of art like a knitted sweater, it becomes totally ridiculous to complain about someone making a sweater that caters to their tastes instead of yours. They’re knitting because they want to knit, and they’re using the blue yarn and adding extra cables to the pattern because they want a blue, cable-covered sweater. Posting that fic or art after it’s finished is like posting their modified pattern for you to freely use, if you want the same type of sweater as them. If you don’t, you can pass it by.
Fandom isn’t a tailor shop where you get exactly the thing you want made for you. It isn’t even a store with a decent stock that you can search through for something you like in your size.
It’s a group of people holding up their knitted sweaters and granny square blankets and embroidered pillows and saying “Hey, look at this thing I made! I worked hard on it, and I’m really proud. If you like it, let’s talk about fibercrafts together!”
*Obviously there are some people in fibercraft clubs who act like this. Those people are everywhere. But it’s a lot harder in an offline club to pretend that your behavior isn’t brining the group down or making people want to avoid you.