While I'm sure pg has his reasons for disliking an article generalizing the program he's built for most of the past decade, he may have wanted to say something almost as a method of damage control. It sure shows that the article struck a chord somewhere, as he usually doesn't respond to these sorts of things.

(Though I do enjoy the fact that his response scores at best a three on his own scale: http://paulgraham.com/disagree.html)

This article purports to be a YC founder's recollection of YC. Pointing out that it's not is not simply an ad hominem.