If someone tells you something in private in a public square in a way that nobody else in the public square can hear it, like lowering the volume of their voice so nobody else can hear, then it is possible to discuss in private in a public setting. There is no obligation to immediately share that private information with the entire public square just because the public square was used. This isn't some FOSS with a licensing agreement that says it must be made public.
You can use the features of a social platform to share with a chosen group of people while not allowing the entirety of the platform access. That's what private means. Not respecting that for sake of "it's a public platform" is just that person being a dick. Whether that's you holding this opinion or a scrapper justifying their manner if not respecting the poster's intent, it's all people with utter lack of respect. It's an AB conversation, and you're trying to be C. We've already indicated you're not the intended audience by setting to private. You doing everything you can to get around that is, again, you being a dick
Having public conversations and having cops insert themselves is.. actually really well established case law. Yes the cops can listen in when you have no expectation of privacy.
We don't want cops having and abusing backdoors but "playing the game" is perfectly legit. The cops do not owe you some sense of playing gently.
I'm not sure this is the sentence you meant. Of course anybody can listen in when you have no expectation of privacy. Without a court ordered search warrant, they can't listen in when you do have expectation of privacy.
If a cop were to gain entry, or have a paid informant gain entry, whether by paying a cover, or bluffing association with a regular, that seems well within the law.
This is not someones house, or your bedroom, or the cops picking a lock & busting down a door. Social media is just an online "third place". It is not work, it is not your home, it is not private.. it is public square, even if you mark yourself "private" and only accept 200 followers instead of 300.
Just like posting things on your social media profile and 1000s of people see it instead of 100s of people you intended.
Another offline analogy would be - talking on your cellphone, you have the right to be free of warrantless wiretap.
However, if you sit down in a bar that you thought "was cool" and take a phone call, but the bar happens to have accidentally let a cop or "narc" in .. and they overheard your end of the phone call because you talk too loud, then what they testify hearing is totally admissible in court, and you are an idiot.
Facebook is not private, neither is Twitter, especially not the profiles on Facebook.
Then you come back with: "but you speak in a way that more people hear you than intended.."
You just changed what I specifically said so it would fit your narrative. Yes, you can be in a bar and think you're talking quietly, but the 3 pints and 2 shots you've consumed means that you're still yelling, just means you're a drunken fool. If you're in a restaurant or some other public setting while sober, you can actually talk to someone without the rest of the public hearing.
You can have whatever wishes you want, but if you are behaving inconsistently with the truth, you're going to spend a lot of time being wrong and having your wishes disobeyed.