The irony? Baum lives in ultra-liberal Boulder, but is also a card-carrying gun owner.
That dichotomy might have inspired this comment from Sundog50:
Dan appears to be severely conflicted, not only by his ambivalence to firearms but his distrust of (other) firearms owners. Perhaps this book is his way of attempting to work through his 'issues'?
Read more on guns in Dan Baum's Q&A with Harper's Magazine readers writing about his August 2010 piece.