Hilarious, no? But then, my father was mildly shocked when he recently found out that I didn't know who Tilmann Riemenschneider was and dissed me accordingly. Thing is, pretty much everybody thinks that their level of knowledge is, by and large, at least adequate.
It comes in handy that the phrase "level of knowledge" is somewhat misleading - there is no objective hierarchy of knowledge so that you start out with the most basic stuff and subsequently acquire information from the agreed-upon next module. As a consequence, it can rarely be said that one person is generally more knowledgeable than the other. I could easily have countered my father's disbelief by asking him whether he knows who Kurt Cobain is.
People make this big song and dance about having or not having knowledge, but I cannot remember a single instance in my life in which knowing that Japan and South Korea are different countries was of any practical use to me. But knowledge is great because it gives everyone an opportunity to feel superior to someone. If it didn't exist already, you'd have to invent it.