What an interesting tread, I love lurking on this side of the forum lol! -The stories are interesting and so are the gaggling back and forth by the vocal readers. I notice, most tend to issue out disapproval to these types of fan fictions, however the fact that these treads are so hot and always getting posted in shows some enjoyment in the stories are being had. Whether it is admitted or not, probably in fears of looking like a pervert for the admitting.
So (hint) writers take note of this.
Then again there are probably those who genuinely do dislike it, but come back again for the after story, gaggle about the story. =P