Indeed, and we (the LW community) have to learn to tell the difference between deliberate trolls and misguided rationalists for our moderation to be effective. In the same way that replying to a troll is a mistake in that it feeds their attention craving, not replying to a wrong non-troll can be a mistake in that they don't notice their error. Maybe a lower downvote limit (4xkarma) would help break aforementioned habit.
Then there's the possibility that someone enjoys intentionally pretending to be clueless as a means of trolling and further enjoys that it disrupts people's instinct to provide guidance to misguided rationalists.
http://wiki.lesswrong.com/wiki/Deletion_policy
This is my attempt to codify the informal rules I've been working by.
I'll leave this post up for a bit, but strongly suspect that it will have to be deleted not too long thereafter. I haven't been particularly encouraged to try responding to comments, either. Nonetheless, if there's something I missed, let me know.