That's what bothers me about the article. It's about instructing a class, a way of going through motions, not about teaching any individual. What about the third grader who doesn't know Roman numerals? What about the one who can't read "ten"? What about the one who has only eaten a bag of Cheetos in the past 24 hours? Or the kid on the autism spectrum and the one who saw his mother beaten by her boyfriend last night and just about every other night for as long as he can remember?
How does this work when the 11 year old third grader hits Jamison in the back of the head with a book and the quiet girl wants to use the restroom because she is sobbing just like yesterday?
The reality of third grade isn't theoretical. Yeah there are little pods of protected well cared for children. There may even be a sweet spot where none are smart asses and love the call and response and each is equally bright and learns the same way. Just look for the full pony rack by the school front door and the M&M truck backed to the cafeteria loading dock.
The fount of well meaning amateur pedagogy is not the solution to the woes of public education. The lesson of the article is that kids can be incredibly kind and polite to adults.
[Edit: None of which is to say that I think trying to teach the ideas of boolean algebra to 3rd graders isn't a good idea. I'm all for pushing the limits of children's intellect.]