There are roughly two positions being expressed in the debate about privacy online: "Websites are violating user trust and that's wrong" and "Get over it, there's no such thing as privacy anyway".
The problem is that the pundits in the latter camp tend to be affluent, powerful, male, straight, white, or all of the above. To them, users should just "get over" being violated. I disagree. These pundits have probably never personally feared rape, an abusive partner, or a corrupt authority. Living in public is a solution they think they can afford, but many people can't.
The idea that personal information should be public by default is deeply flawed. "Those who care about privacy should check the privacy settings often, or just opt out", they say. What they are describing is a space that imposes the highest maintenance costs and the heaviest burden of technical understanding on the users who are the most vulnerable. That's not a safe space.
If your users do not understand your privacy UI, it is not they who have failed; it is you.