People don't want children to know what they need to know. They want their kids to know what they ought to need to know. If you're a teacher you're in a constant battle with mildly deluded adults who think the world will get better if you imagine it is better. You want to teach about sex? Fine, but only when they're old enough to do it. You want to talk politics? Sure, but nothing modern. Religion? So long as you don't actually think about it. Otherwise some furious mob will come to your house and burn you for a witch.