It's incredible how it's hard to get away from Facebook and the likes. In my last phone I never even installed Facebook. Yet the new android update install Facebook on your phone without your consent.
I'm sure they can spy on you without even installing the damn app or even opening an account, but not sure what to do about it.
You're right though, for anyone who wants a complete lack of privacy, going off the grid may be the only option I'm afraid.