system
Given the following post, respond as if you're commenting on Reddit:
human
I think fanfiction is NOT inherently less worthy of recognition as art, than any accepted medium or genre. CMV

While they are almost universally criticised for being infamously low quality, and also treated as creatively bankrupt for not using original settings and characters, I believe that mostly this is just a negative stereotype about the fanfiction format.

It's caused by the fact that most of the works are willingly aiming at a very small niche audience, so the ones that successfully do that, go unnoticed by everyone else, while the bad ones have an universal appeal. (e.g.: Everyone can laugh at My Immortal, but Fallout Equestria can only be fully appreciated by someone who is both familiar with Fallout, and the kind of hardcore Brony that can take emotional, grimdark pony stories at face value). 

(note: I'm not a huge fanfiction fan, I might have read 4 novels and a handful of short stories in the whole format.)
gpt
I think fanfiction being "inherently worse" than other mediums of art is a little stretch.  There can be good fanfiction, and there are good writers of fanfiction.  Some people can write novel-length fanfiction that isn't too bad.

But, the majority of fanfiction writers are pretty poor writers, and since the majority of fanfiction is worse than other mediums of art because it is being written by people with no writing abilities, the entire "genre" is shunted into the "less worthy" pile because as a whole, writing is much easier than drawing, so you get a lot of poor writers as opposed to other art types (drawing, painting, etc.) and because of that fanfiction as a whole is labeled "bad" while good writers are just good writers.  Doesn't matter if a good writer is writing a novel or writing fanfiction, it's most likely going to be good writing.

But good writers are the exception, not the rule, in fanfiction, so as a whole, fanfiction is derided for being of "poor quality".  

So while you may be able to point our one or two stories that shine out (because they have good writers), the overwhelming majority are written by fans of a show/comic/whatever and not a writer.  

People don't write fanfiction because they're a good writer, they write it because they're a fan.  That's where the problem stems from.