I wonder if you are a parent? Absolutely privacy must be honoured and respected. Unfortunately technology has taken us into a world very different than not so long ago.
Safety is key. My 13 year old has a cell phone (which I swore she wouldn’t get until she was 18, but there’s no such thing as pay phones anymore), she also has a couple social media accounts (not fb or tumblr). She knew the rules from the get go. When I ask, I am allowed to look to see what’s going on. She knows not to add pictures, or tell where she lives, etc. But she’s still 13. And there’s been a few times we’ve deleted things that may have been too revealing.
My neighbour has a daughter in grade 6. A boy in her class has an ongoing contest running on his Instagram account. His top 3 Hoes Of the Day. The girls are excited when they “make his list”. My neighbour would never have found this out and been able to talk to her daughter about it if she had “not been invading her privacy”.