We are all ignorant of most things, there is simply too much to know. We all have blind spots, things and experiences so unfamiliar to us that we have a very hard time learning them. It was hard for me to learn that yes I did have unacknowledged white privilege but I finally did learn that. There is no shame in being ignorant if you are willing to learn.
There is shame in willful ignorance though, the refusal to even try to learn something. Unfortunately there are far too many people in the world who are willfully ignorant. People who use religion, dogma, or pseudo science to support their prejudices. They want to believe in creationism, the protocols of the elders of Zion, homeopathy or that Obama is a Marxist and refuse to consider any inconvenient facts. They would rather remain ignorant then change their beliefs, they are willfully ignorant. The theocrats, the men's rights advocates, the climate change denialist they all are willfully ignorant.
Update: Frank Schaffer has a excellent essay highlighting just how toxic willfull ignorance is to our culture and nation.