John Scalzi is in fine form:
What makes this an error is the tangential fact Mr. Roberts is a science fiction author himself. Here’s something that we in the kvetching industry like to call a “pro tip”: If you take the time to squat and pinch off a steaming ass-loaf of condescension onto the heads of the people most committed to the genre of literature you happen to write in, you may find they will remember that fact when they see your books in the stores. As in “oh, here’s the book of that guy who thinks my taste in literature sucks.” How motivated does that make the average science fiction fan to buy a book? Well, you know: How motivated would it make you?
Now, I assume Mr. Roberts didn’t intend to come across as arrogant and hectoring to his primary audience, because very few people so willfully attempt to ankle-shoot their own career, even the ones with an academic aerie such as Mr. Roberts possesses. I suspect he believed he was being stern but fair. However, I also suspect that science fiction fandom, not in fact being comprised of students who have to sit for a lecture in order to graduate, may have its own opinions on the matter. In the real world, people don’t like being told, while being gently and paternalistically patted on the head, that they’re goddamned idiots. Especially from someone who then turns around and hopes to sell them a book.
The short form of this is to say that it’s one thing to believe a book on the Hugo shortlist (or, as is the case of Mr. Roberts, all the books on the shortlist) is or are mediocre. It’s another thing entirely as a writer to criticize a reader (and someone you’d presumably like to make your reader) for his or her taste in books. The first of these is perfectly valid; taste is subjective. The second of these makes you look like a jerk to the people upon whom you presumably hope to build your career.
Which is of course perfectly fine, if that’s what you intend to do. I’d just make sure that it is, in fact, what you intend to do.