I feel like kids don't really have TV anymore like we did growing up--they're watching youtube (and a lot of Kpop has come into vogue in the States because of Youtube) so they see Youtube stars the way we saw TV shows growing up. And so when we write fics about like...TV...then they think, well I can write about my favorite characters I watch, too. There's a disconnect there about when it's appropriate and not appropriate because I guess they figure if someone is famous enough, then they should just take whatever abuse from their fans.
Like writing a fic about JennaMarbles is a completely different thing that writing a fic about Naruto. Like I see JennaMarbles as just someone who got Youtube famous, a person who has real human problems and is not someone that I personally know at all, but a fan watching her from when they were a child would see this character that they've created a relationship with in their head because they watched her every day for like...years. They wouldn't see her as like...someone that is a person.
And like since fanfic and fanart is so front and center and such a quick way to get eyeballs on your work nowadays (like especially in the last 10 years it's become imperative to gaining a following) they're gonna write it. And if they think that writing poorly written sex scenes will get them even more views, they're gonna do it.
I feel like this is what happens when we don't value original work--we sort of push kids into posting erotic friendfiction that maybe should stay a joke between friends and not like voiced on the internet or even shown to the people that they're writing about. But again, like if fics make you famous...that's why they're doing it. They don't care if breaches boundaries.