The thing you touch on at the end—not quite privity, not quite secrecy, not quite privacy—is the thing I wish I had a word for.
It’s exactly this ur-privacy, though, that people find missing in their lives and are trying to express a well understood, if cloudy, desire for. It’s also something that I tend to agree with the various European governments on, despite my annoyance at the “I know it when I see it” nature of the thing.
So the problem here is that we're trying to make clear cut discriminators when the world has gotten a lot messier. Unfortunately legal systems require discretization, because it is easier to legislate clear boundaries (laws are piecewise functions -- if-then-else). But the world is messy and it needs to be recognized that those discrete boundaries are fuzzy too (i.e. they are guides, not hard fixed and objective boundaries). Probably also coupled with human propensity to discretize continuous variables due to the compression effects. This really is why we have many "know it when I see it" definitions rather than hard rules and you may notice that as complexity is increasing (making this more common) and so is the disagreement with said loose definitions. Then we have a core problem of communication breaking down because everyone is working off a different set of assumptions, assuming everyone else has the same assumptions, and unwilling to accept other bases because our assumptions are objectively generated ;)
In all versions of modern English that I’m aware of, “public” is an antonym of “private”. In all conversations around this topic, they are often treated as though they are not. There’s an intuition gap that you rely on your conversational partner to cross. What you do is say “I have a right to privacy, and by privacy I do not mean literally private, I mean incidentally non-public, due to circumstance”, only not in so many words. It’s the way I talk about it as well, because there’s no well understood and unambiguous way to describe what I just called “incidentally non-public”.
Assuming, of course, that you accept that public and private are antonyms, you can demonstrate this intuition gap by instead of talking about public and private, using another pair of antonyms and talking about up and down, and instead ask the question: Does everyone have the right to be up while down?
That’s obviously a terrible and nonsensical question, but I feel it is exactly what some people read when they encounter someone’s desire for privacy in public. How can you be private in public? How can you be up while down?
This isn’t sophistry or maliciousness: it’s a real way that real people interpret the conversation. Failure to recognise the intuition gap is what leads to a failure to understand the other person you’re talking to.