The book covers functional programming because Clojure places a heavy emphasis on functional programming, and learning it is essential to learning Clojure. The book is not "Functional Programming for the Brave and True, with Clojure as the Medium." That doesn't mean that I'm merely "going through the motions" and am "not fully committed" to helping people understand functional programming, and it's bizarre, presumptuous, and rude that you would suggest that. At this point, it seems to me like you're merely being argumentative.