That's not the aspect of politeness that I take from that quote. What I see there is a rant against the people who think it's outmoded and archaic and overly formal to say "please" and "thank you", to wish their cashier or waitress a good evening, to smile and nod to passersby on the street.

I'm with you on the dishonest part of politeness; I've got no time for that. But this also can be applied to how a given honest remark is made. There's a world of difference between saying "I disagree with your statement, and here are some data points to support why" and saying "You're wrong, you're an idiot, and you're also [insert slur here]."*

*Probably either in all caps or none :P