they need Reality not just as the fantasy that they use to train their behaviors/reactions to things, but as a way to set in stone the social practice of believing authorities, because the only way to gain insight onto Reality is by confirming it with another person, but often not just another person, a person with the right credentials or social position
they tell you that you can Know things for certain as a way to teach you to accept certain logics where they feel their framework to be advantaged. accepting there is a Truth to things really, is to accept that there is a correct perspective to view things from and very very very frequently that perspective and the state/social authority occupy the same place in peoples heads and with it comes all other sorts of assumptions that they'll throw into the conversation