I'm a little tickled by the author's clear concern about the idea of giving coffee to a child, yet in our society we give adderall - amphetamines - to preschool aged children. Caffeine really seems pretty tame in comparison.
It's not exactly fair to assume that the author isn't also concerned about the prescription of adderall to kids as well.
We give amphetamines to children only with the consent and supervision of a doctor. Whether or not it's a good idea, it's certainly a more controlled environment than just drinking caffeinated beverages on your own schedule.