Earlier quoted context omitted.
I think this argument is logically flawed. When you say public means not private you are glossing over the fact that public never before meant "available via digital media to the world." Instead it mean a public which had a localized context. Doesn't mean you are wrong, but you're paving over this obvious fact.
But what practical difference does it have that it's "available via digital media to the world."? Are you just opposed to people not in your physical location seeing you? Why?
But of course, that ship has sailed in much of the world, with the ubiquity of surveillance and the dearth of opposition.