I am trying to write a python macro for libreoffice calc but when I go to tools/macros/organize macros/python, all options are greyed out.
To write Python macros, the easiest way is to use APSO. Or, use your favorite text editor and then go to Tools → Macros → Run Macro.
From https://wiki.openoffice.org/wiki/Python/Transfer_from_Basic_to_Python:
On the current version, script organizer for Python do not provide the way to manage script files. So you have to manage yourself.