It's an interesting characteristic of human language that the word 'ignorant', which I find pretty innocuous if used on its own, comes across as a lot harsher when put in the company of 'stupid' and 'insane.' Some kind of context-building I guess, the brain automatically assuming that the author's point is simple and uni-faceted.

I think what happens when I read the word in this context is that my brain automatically inserts the word "willfully" before "ignorant." I mean, it's trivial to say that, for instance, members of uncontacted tribes are ignorant of evolution, but that's usually not what people are talking about when they use the word like this.