Because if you filter what he's saying through the lens of a casual observer, the basic point of his post is just as relevant.
"In my experience social scientists are very in tune and correct about some things. They know the way that relatively rich, educated, genteel, polite, educated undergraduates think. They know how other extremely educated, privileged academics think. And living in one of the most intellectually inbred worlds possible, they believe they know how all people think. "This is how we all are, to some degree. It's why we're capable of holding different opinions in the first place - if all people operated under the same values and logic, there would be no political parties.
We all understand our own social group very well, and we have difficulty comprehending how someone else could think differently: "How could these Republicans want to ban abortion?" "How could these Democrats want to legalize gay marriage?" And these differences right here are some of the smallest differences you can really have, given that they're opinions largely held in their most vehement form by members of the relatively affluent and educated middle and upper classes of America.
I like the way that Rory Miller explains it in his post (but then, I tend to like the way he explains most things. Read his books; they're fantastic). Whether you're applying it to security (dirtbags out to rob you think with different logic and codes than you), to writing (my 18th century Indian heroine would not think like a 21st century white woman), or just to daily life (this person's opinion truly does make perfect sense to them, even though I feel like they're speaking Klepton), it's worth a second glance.