I'm also the mother of a son, and I couldn't agree more. In fact, it seemed to ramp up and take on a life of it's own over the last decade, it wasn't quite so obvious in my small area when my son first started school.
I agree with the author, as well, except for this:
A female teacher, especially if she has no male children of her own, I’ve noticed, will tend to view boys’ penchant for challenging classroom assignments as disruptive, disrespectful—rude.
Having experience in the workings at my son's school and as a volunteer teacher, I find, after a decade (at least) of hammering it home, friends of mine who also volunteer, who also and coincidentally have sons only, many of them are just as bad or worse with what they view as 'disruptive'. In my own group, once I started - or shoould I say stopped! - focusing on the fidgeting and such, their overall behavior improved and we had a more productive class. We were originally instructed to 'stop' such behaviors because they were considered 'acting up'.
I remember an article written by a teacher. They were recounting a potential problem child they had in their class. The child, a boy, would come up and constantly "bump" up against them. This teach finally had enough and was going to send the boy down the hall then next time. Before that happened someone told them the "bump" meant the boy wanted their attention.
After reading this I realized my two boys did the same thing. they would make small physical contact when they wanted me to focus more on them. I started responding appropiately and things were much happier.
Don't know if girls do this.