Strictly from the standpoint of the Human Animal crawling out of the muck: having read enough and been taught enough to be considered sophisticated (?, learned? , whatever the opposite of ignorant is) is not a natural state.
Ignorance is actually the default. It's nice that so many people imagine that they are not, but I think the expectation would be that you are.. until proven informed.
I would say it's centuries and centuries of improving our knowledge that give people the idea that being knowledgeable is the standard, or at least should be.
BUT I would add that we have a very skewed image of what "non-ignorant" is : we usually think of someone who has studied, can read and write, etc...things that are validated by an education system.
However, one can be "non-ignorant" without ever going to school, but the West-European system has taught us look down at those people without trying to see what kind of knowledge THEY have. Something that has lead to a lot of traditional knowledge to be lost in Africa, for example.
Hell, the very word "ignorant" has become somewhat of an insult, while it originally means "one who does not know". Why insult someone who doesn't know, instead of asking what does HE know that might be interesting or, better yet, help him to actually know?