I am a former high school teacher working with Chicago kids age 15-22 (yes). I don't know about you, but they're children to me. They are simply not equipped with enough information to make rational choices in a system that has either by design or evolution _completely failed them_.
A child is someone who is not cognitively capable of distinguishing right from wrong. A 15-22 year old is fully capable of doing that. They may have a hard time fighting various pressures and doing the right thing, but that's a qualitatively different issue. (And in fact, most adolescents are perfectly capable of doing that too.)
> So the changes that happen between 18 and 25 are a continuation of the process that starts around puberty, and 18 year olds are about halfway through that process. Their prefrontal cortex is not yet fully developed. That's the part of the brain that helps you to inhibit impulses and to plan and organize your behavior to reach a goal.
> And the other part of the brain that is different in adolescence is that the brain's reward system becomes highly active right around the time of puberty and then gradually goes back to an adult level, which it reaches around age 25 and that makes adolescents and young adults more interested in entering uncertain situations to seek out and try to find whether there might be a possibility of gaining something from those situations.
That doesn't say that adolescents can't distinguish right from wrong (which is what I said). That says that adolescents often lack the impulse control to do the right thing consistently.
To give you an example. My six year old doesn't really understand why she shouldn't eat junk food. She can kind of understand that she shouldn't do it, but the "why" is beyond her. Thus if she eats a bunch of junk food, it's not her fault, it's my fault. "Children" are held harmless because they lack a basic prerequisite for culpability: the ability to truly distinguish between right and wrong.
Having the cognitive ability to distinguish right from wrong, but lacking the impulse control to do the right thing is different. I know I shouldn't eat junk food, and I'm fully capable of understanding why. But I have trouble doing the right thing. If I eat a bunch of junk food, it's my fault. I am culpable, not my mom.
Calling someone a "child" is to negate their culpability. That's not an appropriate label for an adolescent. If lacking impulse control negated culpability, I'd suspect you'd find that a lot of adult criminals had poor impulse control. That doesn't make them "children." (Contrarywise, when it is demonstrated that an adult lacks the capacity to distinguish right from wrong, that does negate their culpability, in the same manner as for children.)
that were old enough to hold up a gun/knife to someone and make a demand.