How is Spring Boot "enterprisey"? It makes modern java programming simpler and more accessible by hiding some of the unnecessary complexity. It enables things like https://jhipster.github.io/ which to me is the Rails equivalent in the java world.
And I'm a big fan of Clojure, but it's not because Clojure is cool that Java becomes de-facto a big pile of poo. People have been drilled by so much FUD about Javaland that they simply can't stand to try it correctly without preconceptions.
This makes me shiver in terror.
There's still a ton of "enterprise-grade" shit in Spring, you just aren't forced to use it if you don't want - but it's always there, lurking behind the scenes.