One of the lessons drilled into me during grad school: a writer doesn't respond to critics. Let your work speak for itself. Once you start trying to explain it, you've lost. To explain is to demystify. To explain is to do the reader's job for him. And so on. In writing workshops, we were never allowed to join the conversation about our work. "Just listen and learn." I remember people sitting on their hands, putting the silent finger over their lips, anything to stop the words from flowing. A good discipline.
There's a certain loftiness to this rule that seems incompatible with our age of author accessiblity. To my ears, it sounds a bit like an eighteenth century country lord admonishing his offspring. "A gentleman does not engage in trade." Even so, there are plenty of examples from recent history to reinforce the point, authors engaging their critics only to make themselves objects of ridicule. For the most part, responding to critics seems to be a self-defeating strategy.
And yet, it's so tempting. With the proliferation of customer reviews and book bloggers, airing your opinion about a book is easier than ever. That's great for writers, who tend to be publicity starved, but it's a two-edged sword. Noboby has spent more time thinking about your book than you. Nobody wants to talk about it more. But you can't. Not in that venue.
Answer the critics on the page and let the words speak for themselves.