The weird thing about the cannabis mention in this article is how irrelevant it was to his story. He mentions smoking up so he can explain how hard it is to do algebra while high. Uh, and? Is your daughter doing her algebra homework stoned?
I got the impression that he mentioned it to signal that he's a "cool parent". But that hurts his point; it makes the rest of the argument seem like it might be the product of aloofness rather than productive, tactical concern.
The way I read it, the marijuana references tie back to his youth and are meant to contrast his youth to his daughter's. I actually found them pretty powerful. The feeling I came away with was: is this (ultimately low-value) homework causing her to miss out on opportunities to be a teenager and do teenager things, like smoking weed behind her parents' backs, making out with other teenagers, and making other irresponsible-but-ultimately-valuable decisions in her personal life? In a way it made me sad for her.
I got the impression that he mentioned it to signal that he's a "cool parent". But that hurts his point; it makes the rest of the argument seem like it might be the product of aloofness rather than productive, tactical concern.