There is a category for fanfiction, so why the hell is fanfiction being put under the original prose category? These so-called writers must have some reading capability if they are able to string together the letters of their stories' titles.
And then there are the people who put RPs under prose (not that these should be anywhere but scraps to begin with), and actual prose under poetry or script. And don't even get me started on the special snowflakes and their "Free form prose". Wtf? Do they not teach basic lit forms in school anymore?
Tl;dr: Too much miscategorized crap in dA's Lit categories.