Oh, please, you can't take him too seriously. And -- you may not know anything about EY or HPMOR, I don't know, but one day about, god, four or five years ago now? he decided to write a spinoff of Harry Potter in order to drum up donations for his research institute. On a whim. Having never written anything longer than six chapters in his life. Now it's got about 15000 favorites on fanfiction.net, which is the most ever, I believe.
I disagree, for two reasons: one, Yudkowsky can write. Really well. He's written other short fiction, he's written five thousand word essays on ethical relativism, on whatever -- and it's all uniformly fascinating. He has voice or flair or style or whatever the English teachers are calling "it" these days. Two, of the ~million Harry Potter fanfictions that exist, 1 percent of 1 percent are of professional quality, and that's still quite a few stories. Not many, perhaps, and it takes a long time to find them, but they're there. Of course, those stories aren't usually the ones with the most reviews on fanfiction.net, which is a kind of shitty website anyway -- which is what makes HPMOR so surprising.