It comes from the same place "scientific" racism did. It's an excuse to not even bother trying because "muh hormones".

Adult initiation rituals tend to be 13-14 in every pre-industrial society (current and historic) because that's when it happens biologically; it is therefore not a surprise, in Western countries where it's delayed by a decade, that the people from 14-25 are not developing correctly.

The first step to fixing this is to acknowledge the problem exists.

It might be unique to our era (of capitalism), but its definitely true that even if those teenagers appear to be polite, you must remember yourself what it was like to be a teenager, how frustrated and angry and anxious you were all the time, how little you really knew about the world, even if you were nice in public. I don't think those basic impressions you get are definitive.

I don't know how to define 'correctly' here, but in politically and economically advanced countries they develop in much more healthy and productive ways. People who are forced to be adults at 15 often never get a chance to mature.

The operation of such societies should be regarded as an optimization for current circumstances rather than an optimal strategy. If you think what we are doing is poorly suited you are going to have to justify that position on its own merits.

They learn how to not upset Adults (and how to effectively upset them too), how to be pleasing, how to stay out of trouble, how to utterly lie and not get caught. Teens are advanced children in this respect.

Now you might think you are too smart to be fooled, and that of course is your downfall (didn't you read in school about hubris and arrogance?). The kids are humans, it is very high stakes for them and they study and hone every technique. For them it is their most productive skill. You are massivly outgunned. Adult.

You might think you are good-willed and trustworthy, but you are inescapably an Adult. You have that unchecked power and have been corrupted by it. Even if you are truly a friend now you can switch on that power in a moment if something bothers you, at your whim, by your mood. It's like petting an unrestrained lion; no matter how calm and playful it seems, licking you, nuzzling you, purring ... you are paying very close attention and tailoring every move to its pleasure. What if something scares it?

I work to maintain great empathy for children's position (hard to do, because I am corrupted by unchecked power). When interacting, I keep my mouth shut - a whispered syllable dominates the conversation, even if to provoke resistance. I listen attentively: are they speaking with their own voice, for their own cause, of their own perspective? A good signal is if it's too pleasing, if it fits so beautifully and joyfully in my beliefs, relieving all tension - here is a child who understands! Lol. Other people, especially with the vastly different experience of a different generation and of childhood, will have very different ideas and perspectives, many hard to understand or uncomfortable. Just think what you sound like to them.

When kids do that pleasing thing, what response do you see? You see Adults compliment them - 'what fine children!' The Adults are suckers, and if you think back to your teenage years, you know it. Adults are so easy.

There's another issue here. I was once at a casual Adult dinner party and a couple had brought their only child, a 13 year old. The child, as far as I could tell, was the Adults' best friend and they said as much. I tried engaging the child away from their parents and give them some space to be themselves, to be valued as themselves. They said they wanted to be there, with Adults (lol), because 'who wants to hang out with 13 year olds?' So truly heartbreaking.

It's also "point of reference" - kids more isolated from other kids will latch onto adults as their "reference people" they compare themselves to and model behaviours from while kids more socialised with kids will reference more onto near peers.

Isolated kids are commonly more intellectually precocious but less directly practical and (naturally) tend to have a bit more trouble connecting with peers. It's not unusual.