This is the way Clojure works too. Nil is treated as an identity/neutral element. This goes beyond lists: in contrast to Common Lisp who equates nil to the empty list, Clojure maintains a distinction and you're supposed to handle nils by correctly implementing functions. This is as easy as using clojure's core functions, they all have been tailored to handle nil as the neutral element.

As a consequence, in Clojure, nil's neutrality extends to other datastructures, for instance (hash)maps. (assoc nil :some :value) => {:some :value}.