It all comes back to the definition of “privacy” and whether it is reasonable to expect that information, once posted to a publicly accessible forum, can be considered “private”.

Is it even reasonable to expect information that isn’t transmitted via some method which features end-to-end encryption to remain private?

Maybe I’m just old-school, but I’ve lived my life by the philosophy: “if it is private, don’t post it” Frankly, this should be the first thing we teach kids about the internet, IMHO.