Earlier quoted context omitted.
Attacks on the author aren't the best thing in general ( https://upload.wikimedia.org/wikipedia/commons/a/a3/Graham%2... )
I agree that ad hominem attacks are generally counterproductive when your goal is to evaluate an argument. However, when deciding whether to invest hours reading and discussing his latest arguments, the author's credibility is a factor.
There is no fundamental argument he makes that can be refuted soundly, besides just disagreements in opinion.