They come from the "average man", intellectually cowardly and living by inertia, and whose entire ideology was most likely fed to them by mass media and propaganda, IME. They've never thought independently about anything deep, and if they did at some point it brought nothing but frustration and further confusion to their lives so they're triggered by anyone trying to have a thoughtful exploration as it might bring the house of cards that is their worldview down. As such, their gut reaction is to "shut it all down", using whatever poor argument they have at hand to do so (because if they were wise enough to be honest about their reasons for being against this potentially productive convo, they wouldn't react this way in the first place). 🤷