None of this even remotely true. I've gotten into Clojure without knowing jackshit about Java, almost ten years later, after tons of things successfully built and deployed, still don't know jackshit about Java. Mia, co-host of 'Clojure apropos' podcast was my colleague, we've worked together on multiple teams, she learned Clojure as her very first PL. Later she tried learning some Java and she was shocked how impossibly weird it looked compared to Clojure. Besides, you can use Clojure without any JVM - e.g., with nbb. I use it for things like browser automation with Playwright.

The tooling story is also very solid - I use Emacs, but many of my friends and colleagues use IntelliJ, Vim, Sublime and VSCode, and some of them migrated to it from Atom.

It might not be a problem for you, but it has been for many. I did start by reading through 3 Clojure books. The repl and the basic stuff like using lists is all easy of course, but the tooling was pretty poor compared to what I was used to (I like lisp, but Emacs is a commitment). Also, a lot of tutorials at the time definitely assumed java familiarity, especially with debugging java stack traces.