Unless we assume that these people are completely ignorant of the public nature of their status updates, then this isn't a privacy violation. Is the argument that Facebook defaults to public and makes it confusing to change settings?
But that's exactly the point. Normal's don't get it.
Behavioral Economics studies show that when something is made a default, about 90-95% of people will keep that default. So, when something is made "Opt out" by default vs "Opt in", the vast majority of people won't bother to change things.
So, when Facebook changes this behavior, you can assume that going forward 90-95% of their content is going to go public.
Most normals that use Facebook aren't going to care until it starts biting them in the ass. While, many geeks instinctively understand the huge implications of everyone's status updates being made public.
Granted, you may not care, and I certainly respect that. But, at the same time, I have a hunch that many Normals, if they truly understood the full ramifications of what may happen might substantially change their behavior, or choose not to use Facebook at all.
Another issue, is this: Does making users Facebook posts public by default benefit the users? I think it benefits Facebook tremendously, but I'm doubtful how many users it's going to benefit to have their "rectal surgery" posts made public.