Yeah, I've seen the ignorance, too. I get questioned all the time about the long hose, and nine times out of ten it's from someone that's less that polite about it, and in a position of leadership (like a divemaster, for example).
What they're showing is that they weren't paying attention in class. The long hose setup is on page eight of the PADI AOW manual, and specifically introduces the OW student to an "AOW setup that has the benefit of being able to allow for an OOA donation in an overhead environment."
I just look at them quizzically and say, "Page eight, PADI AOW manual... Were you not paying attention?"
That usually shuts them up.
Of course, I don't usually say something like this unless they're rude to me first, like your guy was - some people actually do have genuine interest. But if they're one of those divemasters who became divemasters in 50 dives or less, and shouldn't be in any position of leadership to begin with... Well... Hey, just tell them that maybe they need a review.