Have you met the author? Peter is opinionated, but most of the time he has a valid reason for it. As a writer and a programmer, a good keyboard is a necessity for his work. (I'd bet he's typed as many or more lines of code than a good number of folks here at HN.)

At work we have have folks that order and try out several different keyboards before settling on one that meets their needs. When a programmer makes 80K, a few extra hundred dollars at the extreme to make them efficient and happy is noise in the budget. Even our interns get their choice.