That's you and me. I have something somewhat legitimate in there. I'm also sure you're aware that domain registrar information is rarely changed in a timely fashion, even though they're sending out the yearly reminders to make sure your information is right.
The whole registrar proxy thing is easy money for them. As I recall, they have verbage on the page that strongly recommends using it, implying it's for the safety of your domain.
I've frequently seen that the registration itself is handled by an accounting department, not by the IT department. When I was looking at their pages, it looked like they don't have an in-house IT department. It's probably a contracted web designer who maintains the page, and someone in-house (like accounting) manages the domain. By managed, I mean "pays the bill when it comes up for renewal".
Since it's frequently managed someone who will never check it, it's actually better to let the proxy service handle the contacts. They will (hopefully) update their billing info if there is a change, so the service knows who to send contacts to.