We live in a world that thrives on over-sharing inappropriate things: our sex lives, when our daughters get their periods, the spectacular fall, etc. One only has to look at STFUParents, or failbook (and the many incarnations thereof) to see the many ways we are deciding, as a society, what is appropriate and conversely, what is now inappropriate. It also is what people feel they have a 'right' to know, like telling a woman with 4 kids that she'd better get her husband 'fixed', or some such thing.
You know, when I was growing up, behavior like that was called being 'nosy' - and it wasn't something to be proud of. When one of my older sisters was sticking her nose into another siblings' business, I would ask my mom, "Why does she do that?", and my mom would respond, invariably, with a version of, "She's just being nosy", and it was usually said with a frown (and a sigh).
Unfortunately, I think that my generation and younger generations aren't growing up with boundaries in place - no one is helping us/them decide what are appropriate questions to ask, what is appropriate information to share, and when to tell someone to stick their opinion in their ear.
What to do about it? Oh, I don't know. I'm just here to point out the problems, not fix them, for goodness' sake!