Facebook brings this to the surface. On an Internet without a Facebook-like service, someone may occasionally find a photo of themselves more widely published than they would like. On an Internet with Facebook it happens far more frequently.
The problem is a legal one, not something that facebook can simply add as a feature. (Though they do have a way to report a photo in addition to untagging it. And then you explain why that photo violates privacy laws. https://www.facebook.com/help/?faq=217091804975136#How-do-I-...)