LJ is too slow to look up the exact quote, but I believe A.J. Hall commented in RJ’s LiveJournal that she could understand people not reading slash for moral reasons. Ah, here it comes:
Some people, it is true, who I know and who write slash have difficulty in understanding the “I never touch slash on principle because it can never be canonical” attitude. Most would have considerably more sympathy with a consistent moral position.
I was thinking about that, and came to the conclusion that there is no legitimate moral reason for not reading slash. There’s a moral basis for avoiding smut, and insofar as slash is smutty it falls under that reason, but slash without the smut is not a moral issue.
Why not? We read murder mysteries, even though murder is wrong. Were there an entire genre devoted not only to murder but to the glorification of murder it might be wrong to write in it, but not to read the occasional story. Even in non-fiction, we read about terrible things without feeling that reading about them makes us culpable in them.
The objections to slash are more basic than moral differences, and I think they fall into two categories: the literary and the visceral. A visceral dislike for slash is often identified with homophobia, but it’s more commonly human nature. Heterosexual men, especially, are deeply squicked by the notion. It’s not as strong as the incest taboo, but it’s out there and it’s a good enough reason not to read slash.
My objection falls into the literary camp. I have nothing against reading fiction that’s about homosexuals - I particularly enjoyed LMB’s Ethan of Athos, even though it’s not one of her better works. I don’t even have anything against writing about homosexual characters, be they Willow/Tara or characters in my own original fic. It’s not homosexuality as a topic that disturbs me but slash as a genre. A host of fans explicitly devoted to reversing canon sexual orientations, to writing stories because they are risqué, and to being generally contrary or rebellious do not appeal to me. It doesn’t make me want to know them, to be part of their clique, or to read their stories. The slash description adds no value for me - it merely alerts me that the story wasn’t directed at the general reader but at a subcommunity whose motives and principles I barely understand, never mind share.
I think when RJ exempted “Lust Over Pendle” from the slash genre she meant it in this sense - not that the story wasn’t about a non-canon homosexual relationship, but that it wasn’t about contradicting canon for its own sake. It was not about being slashy. I haven’t read it so I can’t say for sure.
There are other subcommunities of fandom that are just as self-congratulatory and anti-canonical as slash is - J/C fandom comes to mind immediately - but most of them don’t assert or assume a literary superiority over other fans. It is entirely possible that slashers are better writers, overall, than non-slashers, but that’s a matter of statistics which does not make slashfic better in principle than other kinds of fic. Being slashy is not a literary good in and of itself, and no amount of claiming it is will make it so.