I don't know if it's apathy, so much as it's lack of awareness. People are simply ignorant of how the things they say and post on Facebook can come back to haunt them, and when, and with whom, and in which settings. It's a safe bet to assume that most Facebook users simply don't know how Facebook data works, or what its ramifications could be.

They won't know, or care, until they run into a specific case where it affects them -- at which point, chances are, it will have taken them entirely by surprise. (It takes only one off-handed reference to a drunken Facebook photo in a job interview, for instance, to put the fear of God into many users).

I'm not suggesting that people would abandon Facebook en masse if they were better informed about it. And hell, I'm not sure many people even would care all that much. But I bet you'd see a marked shift in user behavior in pretty much any users in college or older. (Basically, anyone thinking about employment).