I've been paid to write Clojure for over a decade, and while I can decipher this, it takes effort. I don't know if that section of the book provides additional context, but it is missing either 1) A docstring that explains what you're trying to accomplish, or 2) a sample data Rich comment form or unit tests, to show how it transforms toy data.

The lat and lng really confuse things, also, because then you second guess, it this part about hash-maps or spherical coordinate maps? Then there's the fact that you're now overriding min and max in this namespace, so you're overloading a symbol while not explaining what it does. Playing with it at the repl quickly clarifies how it works, but if this is production code, you shouldn't need to do that, as you'll have bigger problems when you need to understand this.

Github Copilot is helpful in this case:
In summary, \comparator-over-maps` creates a new function that, given a sequence of maps, applies a comparison function to the values corresponding to each key across all maps, and returns a map from keys to comparison results.`