QuantMech, I think you may be mixing up the concept of a privilege with what it means to be “privileged.” I don’t think those are the same, at least in colloquial English, which I think is why the OED didn’t help you. We can talk about whether something is a privilege or not, in the sense of, say, whether driving is a “privilege.” We can say, though, that Thurston Howell III is “privileged,” and we mean something a little different. I don’t know if this makes it any clearer, but while being white may not be a privilege, being white does make you privileged. I think “advantaged” captures this a bit, but I would say that “privileged” as we are using it here has some of the flavor of both “advantaged” and “entitled.”
As I think about it, Mr. and Mrs. Howell are the perfect examples of this. Even though they were really in the same position as all of the other castaways–especially those who were also passengers on the Minnow–they believed they deserved–and they received–special treatment because of characteristics that were actually irrelevant to their current situation. That’s a privileged attitude.