A slightly simpler explanation: GraalVM solves the startup time but clojure's built-in eval wouldn't work after compilation so you need to reimplement it in a simpler way.
That's a table of library compatibility w/ GraalVM, one reason for incompatibility can be use of runtime evaluation.
I think it's related to dynamic loading of classes (and since Clojure functions get compiled to classes, this might be the issue), not really evaluation per se. But I haven't really looked at Graal native image for a while, so I'm not sure what's the current status.