When I learned Clojure, I also needed to learn about Maven, and POMs, and JARs, and the Java classpath, etc — and encountering all that stuff for the first time at the same time I was learning Clojure meant that I sometimes couldn't tell what concepts were part of Clojure, and what concepts were part of the Java ecosystem. This wasn't helped by the fact that the bulk of the "how to compile Clojure" documentation was written assuming a Java background (thus, assuming people would recognize the familiar Java stuff) — and when it wasn't, it didn't bother trying to explain what parts were handled by Java and why, because it assumed you didn't know Java so why bother explaining
all that Java stuff that'll be foreign to you, let's just gloss over it. So the result was that I was unable to learn how to deal with the Java ecosystem parts of being a Clojure developer, so I had to go learn about the Java ecosystem separately.
Contrast with ClojureScript — It has the same problems as above, but substitute JS for Java and NPM for Maven, etc. I was coming from a web background, so I could easily tell the JS-world from the CLJS-world. That familiarity helped me tremendously in getting up and running.
The situation for CLJS is even better now with things like Planck and shadow-cljs (and Shaun Lebron's cljs/tool and Cuttle before them), since those tools mean you don't even need to install the JDK to get up and running with CLJS (as it should be, I'd argue). The situation for CLJ is a bit better thanks to the CLI tool. But the problems above could have been well handled by the classic non-technical solution: really, really good official docs. That's been getting better (thanks to Alex), but I'm pretty sure it's still going to be more painful to get up and running with CLJ or CLJS than Ruby, Node, etc., sadly.