Another good point. There are cases where people don't understand some things when they watch old movies. But is that their fault? It is when it's a case of ignorance, but not when the movie has dated elements. If my grandchildren ever watch any American sitcom and don't laugh because they don't know who George Bush is (they all had made fun of him), I'd be worried. But who today knows who Hearst was without searching first? Remember: A classic is a movie that survives time. This one is still a classic because that dated allusion may be important to get some of the context, but isn't important to get into the story.
Also, since you insist on looking at me as a foreigner, there are movies that foreigners don't get. But sometimes that's because of isolation. KANE's a good example of the former because it's not an American movie per se. It's about the rise and fall of a businessman turned politician, which is something people from any country can understand. But there are movies like BATTLE L.A. where Yankee pride isn't a theme or context, it's the freaking plot! Oh,and it also as propaganda to get people to join the Marines. Do you expect me to enjoy it? Luckily I try to be as objective as possible, and I hated BATTLE L.A. for its production quality instead!