There's something that strikes me about the "brain isn't fully developed until 25" argument, aside from it being ridiculous pseudoscience.

There's something that strikes me about the "brain isn't fully developed until 25" argument, aside from it being ridiculous pseudoscience. I've argued before that that mainly applies to the part of the brain responsible for impulse decisions, while the part of the brain responsible for considered decisions is more or less fully-formed at 15.

But more than that, it reduces decision-making to a biological function, rather than, as it actually is, a skill. Children need to learn how to accommodate evidence and reason about it. And the thing about "social contagion" rhetoric is that it is a deliberate attempt to prevent children from learning, probably motivated by fear that if children learn to think for themselves, they'll be better equipped to question authority and less easy to abusively control.