I have interacted with a great deal many people in the real world as well as on the internet and I have found that many of those who hold beliefs that one would find "ignorant" are actually pretty knowledgeable of the subject of which they are speaking. It is the knowledge that they have and their experiences with said subject that would make calling them "ignorant" ignorant in and of itself.
Think about it. Ignorant means uninformed. Is it not possible for a person to be perfectly informed of a topic and still have an opinion on it that others who have either differing information sources or different perspectives on the information that they have and still hold an opinion that one would say they are "ignorant" for? In other words, isn't it even slightly possible that one can be informed of a topic and still have an opinion that others do not agree with, or that the mainstream does not agree with?
I say this because I feel that people are too quick to jump to calling a person or an opinion "ignorant". I almost feel like it's a cop-out for giving a REAL argument sometimes or actually attempting to enlighten them with the knowledge that you have - by knowledge, I mean actual sources, not just what you heard from your Mom, what you saw from your kids or what you saw at the grocery store (although anecdotal evidence can add context to an argument, it shouldn't BE the argument).
TL;DR I think "ignorant" is slung around way too often as a means to essentially say "I don't agree with this and because of that, I am going to attack the credence of the person making the statement and/or credence of the statement itself rather than attacking the actual statement". Some opinions are truly born of ignorance, but one isn't ignorant because you disagree with them or have different information/beliefs/sources. This isn't to attack any one or any viewpoint in particular, just a general inquiry. Thoughts?