Have you never experienced this? Someone starts to listen, but screws up their face and starts pick-pick-poking at what you're saying because they don't like it? Most humans in this situation are not looking to learn, they want to make themselves feel right, and for that they need to find one inaccuracy so they can declare the whole thing suspect and go back to feeling good about themselves. If they can't find that chink in the armor, it is possible they will learn in spite of their intentions, and the badfeelz that come from discovering they were wrong about something.