I can tell you that this code is very easy to read if you are familiar with Clojure. In fact, this example is lovely! Seeing this code really makes me wanting to try this library! Clojure has this terse, yet readable aesthetic that I like a lot.
But I completely understand you because at some point Clojure code also looked alien to me. You are not broken for having familiarity with some style of code. Familiarity is something you can acquire at any time, and then this code will be easy to read.
True hard-to-read code is one that is hard to understand even if you master the language it is written in.