By having some empathy? By considering other people's perspectives? When somebody is incapable of discerning what makes the people around them uncomfortable, we call this psychopathy, no?

Social norms are not simply power structures, they're broadly agreed upon conventions that aim to minimise unnecessary suffering/discomfort (I'm not even sure what to say about the notion that recognising the facts of neural development is a scheme to oppress young people). Some are undoubtedly silly. Some are antiquated. Some are even controlling. But some are simply about systematising basic consideration for the needs of others. Or a basic recognition of the fact that some people need more protection than others.

It's a social norm not to use slurs. Not because every member of every minority group will fall to pieces at hearing one, but because some will. It's a social norm not to play loud music in public places. Not because everybody will be disturbed by it, but because some will. And it's a social norm (in this case also a law), not to have sexual contact with minors. Not because everybody under the age of 18 is too immature to consent, but some are.

Not everybody follows these norms, of course. But the receive social censure when they don't. Because if we all ignored these social norms, society would obviously be worse for it.

I certainly don't follow all rules. But that doesn't mean I don't follow any rules. Not all rules are good. But that doesn't mean no rules are good. This is one of the may cases where I think nuance is important. Some rules are obviously beneficial to others, cost little to nothing in terms of time or effort, and the only reason I can see not to follow them is selfishness.