What is the exact path you are placing the userSetup.py? The plugins folder is not correct. It should be placed in the global scripts folder, which on a mac, is under users/shared/autodesk/.
Can you confirm your path that you are placing the script? If it is not placed in the proper location, it will not run. With it being put in the plugins folder, it’s probably trying to load/run it as a plugin, which it is not.