The Washington Post has the slogan "If you don't get it, you don't get it."
You could respond to that by saying "If you don't know to know, you still don't know, so 'getting it' is basically moot." This basically means if you're not exposed to something to know it exists, it essentially doesn't exist to you. I don't think you can necessarily fault a person because of their lack of exposure to things.
I'm wondering what are the parameters of what is reasonable and fair to expect people to know about their immediate surroundings and the world beyond and how much responsibility does a person have to knowing about it. Basically, how responsible are you for your own education/ignorance and the initiative you take towards correcting it? How much of it is beyond you? How do you go about knowing what you are ignorant of? If you don't conceive of yourself of being ignorant of certain things, how do you confirm you are not? How do you test your own knowledge? This is not contained to intellectual pursuits, btw.
I'm not really talking about being an inquisitive person, I'm more talking about levels of exposure to begin the process of learning about what you don't know. This is also connected to getting yourself out of your comfort zone so you can get exposed to what you don't know about. How do you go about this process?
Eek, I hope I'm making sense!