I guess you're right but when I look at it I'm looking at it from the perspective of education for safety.

I mean if a child can't consent to sex because there needs to be a level of maturity for consent to be given then a child can't consent to sex with another child and so why have sex education at all?

Or safety online. We could have a rule that says children can't go online until they're 18 but they still would and so it's better to teach kids how to have a positive online experience, things to avoid and what information shouldn't be disclosed. If we want children to report problems they've experienced online then they need to feel they won't get into trouble or get others they care about in trouble by talking about it.

But you may be right, maybe the rules just don't allow for it.