The professor did link his name/email to the post by mailing us; and he specifically said "Please do not leave a comment on the class blog."
I am guessing he wants students to feel free to write what they think without worrying about being criticized or corrected on every point by aggrieved LWers.
But did he say "please don't tell anybody who I am or where I teach?" This is completely orthogonal to the question of preventing comments from LWers, aggrieved or otherwise.
I wasn't interested in writing a comment on the blog (except possibly to ask where the course was -- and I might very well have done so, since Luke's post does not contain any instruction to the contrary! So if info was somehow being hidden with the goal of preventing comments, it would have directly backfired.).
Link.
Given the positive reactions, I think the professor seeded them with a positive impression of the site's content.