You've already made the crucial step then - you've loaded the code. The author apparently wants to avoid that.

You could get away with parsing the code statically in the most trivial cases, but to do it even remotely correctly, you'd have to parse all the code, and only then format individual files. A lot of work for no good reason, and it wouldn't save you from macro-writing macros.

In a large Lisp project, this would screw a lot of things up. I don't have relevant Clojure example here, but in Common Lisp, I worked on a pretty big codebase (CLIM2), where trying to indent things without loading the code into a Lisp image would screw up indentation in 50+% of the files - because a lot of frequently-used macros were written by other macros.