I believe that the strongest root of bias is society. Paraphrasing Sartre, bias is the others. So I disagree with the other thing the author is conflating: that

I believe that the strongest root of bias is society. Paraphrasing Sartre, bias is the others. So I disagree with the other thing the author is conflating: that society often holding ridiculous opinions is because individuals can't think rationally. It's the other way around: individuals can't think very rationally because they're pressed by society.