I notice too that a noticeable number of people pick up Clojure because it's new and shiny. As a longtime Clojurian I find that attitude can be disappointing to run into, like when you realize a growing friendship will die because they're not serious about living in your city.
I don't claim to know the man but the reasons Rich wanted Clojure are quite concrete, well documented, and rational. Java programs of the time were a particularly heinous form of OOP; we should not be surprised that a clever programmer would grow a preference for a dynamic, functional-first style. He found lisp superior (in interactivity, expressiveness, yadda yadda) and wanted to use it professionally.
To work in lisp required delivering something indistinguishable from a JAR (or other mainstream proglang executable). He had the realization that without immutable data structures baked into the language he'd always be subject to Other People's State.
If you think about these points logically they lead pretty straightforwardly to creating a (pragmatically) functional, dynamic, hosted lisp.