Why do you think the articles are almost entirely fanfiction?

I think may be due to a lack of ideas on what to write for the articles so people just decide to post fanfiction. I have sort of a mixed opinion of fanfictions. I think it gives you insight on other people's views of characters, but it does have the pitfalls that you described.

Wow, this is kind of a late answer, but maybe because most of the articles that would be posted are either opinion, lists, or links on another webiste. With the links, it's easier just to put it in the links spot. I'm STILL working on my TOP REASONS WHY I HATE X-MEN: THE LAST STAND, so opinion articles are either really poorly written, or take a LOOOOOONG time to write. Lists are just...kind of boring to write. Either way, I don't think in this spot, articles are necessarily the most...X-y thing to have. Most people think of X-men as trivia I(quiz), decisions (picks), and looks (do I need to clarify this one?).

I don't have a huge problem with fanficions if the grammar is good, they don't go too OOC, and, like you said, no Mary Sue's. Some apparent Mary Sue's, however, aren't necessarily that, and just a character that did something cool in the first chapter, but the writer decided to stop writing it...like mine. *blushes*