In any work of literature, when the writer uses metaphor and indirect symbolism, she loses control of the meaning of the story: the reader must supply his own interpretation. Not only must the reader supply part of the meaning, but metaphor often entails that the writer has put something of herself in the story that she did not intend. The reader can ask not only what the metaphor means, but can also ask: why did she choose this particular metaphor, instead of another? And, in his exegesis, the reader can also unwittingly reveal something of himself.
So Andrew Sullivan has a metaphorical interpretation of Genesis. I think it's a stupid interpretation, but whatever: the whole point of metaphorical interpretation is that the reader himself is the authority on the interpretation (and Sullivan's exegesis does tell us something about himself). But even admitting metaphor, that the text is not literally true, is just the first step. What strikes me about Sullivan's piece and religion in general is that the religious seem to hold that there is always one authoritative metaphorical interpretation. Sullivan argues his interpretation; he does not read it that way. (In Sullivan's defense, I suspect many outside religion, including in academic literary criticism, share the quest for the One True Interpretation. But that makes them just as mistaken).
Putting aside how a mystery can make sense of anything, Sullivan reads Genesis as a real "fall", and the Resurrection "finally fulfilled by humankind's ultimate, universal embrace of a loving God through the aeons of time." All right, that's his reading. My reading is of humanity's first awareness that we are responsible for our own destiny. We are perhaps resentful, just as children can be resentful when they are pushed out of the nest to fend for themselves as adults. Our "redemption" is not regaining the innocence of the Garden of Eden but rather fully accepting our self-responsibility. My interpretation is just as good as any other, because it is just as much about me as it is about Adam and Eve and the ancient poet who first imagined the story.
No religion could accept my interpretation. A metaphorical view of religion just moves the problem around and trades the authority of the literal meaning of the words for the authority of the One True Interpretation (or perhaps for the most shockingly liberal, a range of acceptable interpretations). The New Atheist project, however, is not really against the Bible (or the scripture du jour) itself, but against the authority to interpret scripture in a particular way. Our project is not to invalidate scripture, but move the "holy" books from the realm of scripture to the realm of the Humanities, to place the Bible, the Koran, the Book of Mormon, etc. (ad nauseam) with the Iliad — not the worst company.