Seems like it should be so simple and yet so hard. I searched these forums too and only found two posts, neither of which are helpful.
Lots of stuff says to get the “secret” or “public” iCal link, but shared calendars don’t have either of those. They also say you could make your calendar public (iffy, but ok lemme try it). Shared calendars also don’t have the option of making them public (or at least I couldn’t find it).
I tried adding my google calendars to my icloud calendar, hoping that icloud calendars would be easily shareable. Nope. Adding them only seems to add them to my Calendar app on my Mac, but when you log into icloud, you only have your basic iCloud calendars, not the shared ones from google.
This is maddening. Surely there must be some way to display a shared “Family” calendar on MM? I saw a big list of the docs of tools for calendar syncing, but they were mostly for Outlook. I didn’t see any that were applicable to my situation. I can’t be the only person who has faced this, but it’s just a bunch of dead ends so far.