Learning diplomacy is like, early adulthood stuff. People lie and shit, you learn that in kid’s shows. This is just another case of a LWer re-litigating something under the guise of inventing new brain jutsu.
That is, sure, you can assume good faith when talking to someone for the first time. But one shouldn’t hold onto that assumption tightly; I think LWers tend to hold onto their assumptions way too hard. Much harder than people who are supposed to be uPdAtInG tHeIr PrIoRs should. Otherwise, why would anyone spend time writing this article?