The way I look at it, it's 'if such can survive peer review, what do people make of things whose authors either did not try to pass peer review or could not pass peer review? They probably think pretty poorly of them.'
I can't speak to this particular article, but oftentimes special editions of journals, like this one (i.e. effectively a symposium on the work of another), are not subjected to rigorous peer review. The responses are often solicited by the editors and there is minimal correction or critique of the content of the papers, certainly nothing like you'd normally get for an unsolicited article in a top philosophy journal.
But, to reiterate, I can't say whether or not the Journal of Consciousness Studies did that in this instance.
...has finally been published.
Contents:
The issue consists of responses to Chalmers (2010). Future volumes will contain additional articles from Shulman & Bostrom, Igor Aleksander, Richard Brown, Ray Kurzweil, Pamela McCorduck, Chris Nunn, Arkady Plotnitsky, Jesse Prinz, Susan Schneider, Murray Shanahan, Burt Voorhees, and a response from Chalmers.
McDermott's chapter should be supplemented with this, which he says he didn't have space for in his JCS article.