If you want to have a private conversaion, social media doesn't seem to be a good vehicle for it. Much like airing your dirty laundry in the town square has been considered bad etiquette, airing personal greivances on the internet seems to be in poor taste.
It must be noted that manners never arise sponaniously in culture, but becuase people fear the consequences of breaching etiquette. I for one welcome the return of politeness to society.
And what if you want to buy stuff for a hobby that you only talk about with a few close friends? Don't use Amazon, or a credit card anywhere, don't use Google to look up products or Google Maps to get to a store, don't use plaintext email or Facebook chat or Whatsapp or whatever else to talk about it with your friends, etc.
It takes a lot of mental effort to know whether or not an action will be "public", which can cause the cooling effect this page talks about. The trend is not people doing stuff in private instead of publicly, it's people not doing stuff at all because there is no "private".
Local privacy is arguably far easier in a city, or in a crowded digital space. It all depends on the context of who you're trying to hide from. I'd much rather trust my privacy to Apple and Amazon if I wanted to quietly buy things no one else in my neighbourhood knew about.
More or less I'm advocating a distributed social credit system instead of a centralized one. In fact I'd say "distributed social credit" is a pretty good term for the social conditions we have spent most of our time evolving in.
Both small towns and big cities have governments. Social norms can include being heterosexual or following a specific religion. Not conforming to those expectations can have physical consequences too.