Knights and Knaves are great for logic puzzles, but they don't come up in real life.
A common thread of many of the posts first linking to Moon noted how odd/ironic/funny/purple it was that Will Shetterly was actually the voice of reason in the debate.
Elsewhere, over on my wife's LJ, I had someone accuse me (and anyone else taking on Elizabeth Moon) of "throwing out the baby with the bathwater," because Moon's post started with some good ideas. (Since the person combined that accusation with the typical party troll trick of flouncing out and announcing that the debate's over, I'm not bothering responding there.)
Much as some of the snark aimed at Shetterly amuses me, both of these statements reflect a tendency (one that I'm often guilty of, myself) of assuming that folks are Knights/Knaves. Because Shetterly said some (a lot, actually) of monumentally stupid things, anything else he says must be stupid. Because Moon made some good points at the beginning of her post, accusing her of racism means that we're
In the real world, almost everyone -- yes, even Glenn Beck, even the head of PETA, even that Freeper who thinks that Jews control the media* -- is capable of also believing in good ideas (or at least occasionally getting something right, much like a broken clock). It happens. Calling them on their stupidity doesn't undercut anything else they believe in, although it does establish them as someone whose ideas might be worth verifying elsewhere.
And on the "it should be equally obvious" flip-side, there's nothing wrong with calling people on their crap when they say something as awful as what Moon says. It's not a censorship issue, or a matter of calling someone names (the same person I mentioned above gets a nice "tone argument" bingo when responding to feste_sylvain later in that same thread). The fact that Moon is calm and generally "polite" in her initial post doesn't change the fact that it's a post filled with hatred and small-mindedness. And calling her on it is appropriate.
*I suspect that "that Freeper" should be replaced by "one of the many Freepers."
ETA: For those who are inclined towards being pedantic, I do realize that the Knight/Knave analogy doesn't map 100% here. The more complex vampire/human one Smullyan introduces in some of his books -- in which humans are honest, vamps lie, but "insane" humans and vamps are wrong 100% of the time, and thus an insane vamp will inadvertently always tell the truth, but an insane human will always lie -- is probably more apropos. But I'm generally disinclined to use the sane/insane terminology in this discussion.