Pro Racket was designed to teach functional programming from the start
Racket is based on Scheme (LISP Family) and is very similar to Clojure. So there are a ton of () at the end of s-expressions (in total give a few take a few the same amount as Java or similar languages). The reason it is easier to learn is that it is not trying to be "Pure" if there is even such a thing in terms of Functional Programming. The great thing about Racket is it has everything included. You get DrRacket for developing programs. You want to add a picture to your software you can insert pictures. If you want to add libraries just open the package manager. The Syntax is an opinion but it really does feel easier to see what is happening since everything is in brackets)
Racket is a really a Programming Language for making Programming Languages. So there are smaller syntax Racket called Student Racket which makes things easier to pick up.