And more power to them! There's nothing petulant about it. Quite apart from the fact that a reviewer may be totally wrong (reading skills having declined drastically), the author's good name is on the line. As well as his sales. Money probably speaks louder here than than personal honor.
I could talk myself into making a legal case out of this. :)
Personally, I would say nothing. As I said in the thread Jon pulled, I always think the author comes out of it looking petulant, and I'm more likely to remember (and avoid) a petulant author than I am to remember a snarky review. Would I have read the book based on the review - yes - despite the negative stuff. Would I read it now? Unlikely. I think if it's clearly the reviewers intent to be snarky or worse, then I think that comes across pretty clearly. A sincere and honest review, even if it's negative, is always interesting to read - I may not agree with it, but, as a reader, I like to know what people do and don't like.
I didn't read it as sincere; I'm not even sure if I know what that means in this context. I did think the reviewer was trying to make herself look clever at my expense, without having bothered to do her homework. Admittedly, though, I was being petulant (the start of the semester here often makes me feel that way), and I'd have undoubtedly been better off to just bite my tongue and move on--which is what I'll do next time. Probably. And Donna, I'm actually sad that you're not going to read my book--could I persuade you with a free, signed copy?
As I've said elsewhere, there's a particular kind of online review that, sincere or not, ought to generate a swift kick in the ass for the reviewer. I don't like the idea of ceding authority to online amateurs that they haven't earned. I have to wade through an elaborate vetting process every time I bring a book to press, and under the old rules reviewers had to have at least some minimal cred, too--somebody was paying them to write book reviews, at the very least. Now it's a complete free-for-all, which is fine, but I don't think we can blame authors who give in to the impulse to jump into the fray if a review seems unfair or lazy or ill-informed. I won't do it again, probably, because I agree that doing so can make one seem to be picking on the little guy (even if the "little guy" roundly deserves it). But at the same time I think it might be a good thing to hold in reserve: you never know, as McFetridge would say, when you'll need to go medieval on their ass.