When I click Full Disk Access in Mohave, I see an empty box with a Header something like "All app to access Mail, ..., and all user data".  None of it has anything obviously to do with the user Documents folder.  Nor does it seem appropriate for a non-top-admin user on a multiuser machine.  Below the box are [+][-] buttons.  [+] opens the standard open dialog to select an app to add.  There is nothing like 
  [ ] Add Python and IDLE

Ned, is Catalina known to have tightened up some security settings?