The article doesn't have BTL comments allowed. Notably, every other article in that series does.
On the pseudo-mature children, I wonder whether this is a kind of "precocious" behaviour. If a child gets lots of attention and praise from adults for behaving in a superficially more adult way when they are young, they are likely to go on doing that as they get older. But it stops looking cute and then starts becoming age-appropriate. That's confusing for the child because something that previously earned praise is no longer effective. I think it also hinders development of more mature behaviour, as the child finds it hard to distinguish between the cutsey version and the actual adult equivalent.
(Off topic, but I think Laurie Penny's essays are an example of this. What was fantastic writing for a 6th form student and indicative of huge writing talent is much less impressive now that she's in her 30s and being compared to mature essayists. But because she was showered in praise when younger, she hasn't been able to evolve her style - perhaps because she mistook being told that her writing was great for someone her age for hearing that she is a great writer.)