Poor Clojure. Rich, I just want you to know that you are beloved. It's just that most working developers aren't of a high enough skill level to move on from Java :-(
I would disagree. Clojure is not difficult to grok (compared to other languages with strong functional emphasis).
"Programming Clojure" is on the list. Is this because a version of the book influenced a later version of the language?
This has been linked on HN many times over a period of 5 years or more. While I don't recall with certainty I expect the list has been added to over time and Rich may have added Programming Clojure with the thought of it being a recommendation rather than considering this view of the list. Obviously I'm speculating.
This was by far the first book on Clojure, it was there very early on when the thinking about 'what is Clojure' was still quite new. The Autor is now in some ways the Nr.2 in the Clojure ecosystem, he has influenced the language quite a bit.