As B.Schneier said, if people post private details, it doesn't mean they don't care about their privacy at all.

Even for those people, it's important that they have some control over what they post. For instance they expect their phone pic to be private to them and the person they sent it to, or they expect their Facebook info to be available only to friends and they expect that they can be able to delete it or change it.

Even if your premise were correct, we have to ask ourselves if it is desirable for society that privacy is dead and I can't see how the answer would ever be yes.