I realized that I was running the wrong keeper_mac.command (the one in folder /osx). It works as expected if you run keeper_mac.command from the top level without moving files. My bad!
Just a heads up, for the free version on OS X, when I ran keeper_mac.command script, I was getting errors: FATAL input is false. Failed to load so-and-so from ./data/contribs/something.txt or Failed to load from ./data/free/another.ttf.
I found that if you just moved the relevant folders into /osx/ folder everything works.
