I think it is often unconscious--the brain's defense mechanism, hearing what they want to hear and seeing what they want to see. I think all of us do it to some extent, although maybe not to the extreme of the type of people we're talking about here. How many times have you thought someone liked you or hated you and thought you had evidence to support that, but then found out the opposite was true? How often have you read a word wrong or misread the intent of someone's post because you were looking for what you expected to see? None of that was conscious or intentional. Of course, there are also plenty of people who are deliberately obtuse because they don't give a crap what anyone thinks of them.