If babies had no idea about the world, they'd not cry for food, or comfort, or attention, or whatever the hell else babies get upset about. They get upset because their ideas are in conflict with what is reality.
Children are often taught to shy away from things which the parent doesn't want them to learn about. Think the kids who are forbidden from learning science. From learning factual things that make the actual world they live in. They are taught that they may substitute opinion for fact. That choosing to believe a fiction about something outranks fact about it. They have been influenced and trained by anti-intellectualism to live a ignorant existence and believe that they are the enlightened ones.