The trope is if you don’t have anything to hide, why do you want stuff to be private?
Ask yourself this:
Can you say what your want, even 1:1, without fearing someone will attack you?
Can you search for and browse whatever you want. Without fear of being watched or found out?
Can you store whatever you want? (don’t break laws) Without fear of being flagged by someone’s policy?
Chances are, the answer to these is at least partially no. That should make clear why you need privacy.