I should've probably clarified: It is difficult to grok Clojure code only in the beginning - when you are new to the language. To many beginners, Clojure code at first may not look very intuitive. That is why I'm suggesting to learn it by "breathing it" - try changing it in an editor/IDE that supports structural editing and connected to a REPL - change an expression, eval it - see the results, expand, eval again, move onto the outer/inner level expression, eval, and so on. That way you quickly get the insight and learn how the language works. And it won't take too long to learn how to comfortably read and mentally parse "static" Clojure code.

After some time it becomes clear - Lisp is not harder to read. For some people, it's the other way around - going back to languages with C-like syntax may feel awkward.