I've read that analysis before and actually do agree with it. I'm not a Snarry fan but am an HP fan. And usually of student/adult ships. Currently have an odd attachment to Snape/hermione but the problem is that LJ wants to get control over what's posted. They are a business.
The PwP analogy holds to a point, but LJ has also said they've never seen a problem with fanfic that's been reported (and I find it hard to believe a PwP was never in that group).
In writing, even a PwP there's still story. Not much of a plot but still more background, so to speak, to it. Unless we're talking the ones that are just sex which I'm afraid I don't see much merit for at all. So even taken without the context of a fan you can still get at least part of the "feeling" of the story being told.
In art you don't get any of that. You simply get what's in front of you, which is one single scene, a part of a larger story.
I'm also afraid, if LJ isn't judging on "merit" because it's subjective (which it is) and they still want to stop what they deem child porn they may just ban all adult material as a whole, or worse, fandom as a whole. Fandom in itself walks a thin line of legality.
And understand I've seen the drawing of Ponderosa's that was the cause, and I think it's an incredible drawing. And not at all child porn. I viewed Harry as 17 because of the context of the drawing but that's not a child. I haven't seen Elaboration's work so I can't really express an opinion there. I also don't draw at all, and almost never write anything adult. I'm viewing this from a somewhat safe perspective in that way. But I'm also viewing it as site owner that does occasionally have to be concerned about content going into my sites. And have regular arguments with people who think my rules are unfair, even though they are mostly protecting my webspace.