The PR author elaborated further in the linked Twitter thread: he believes that a policy of assuming good faith is bad on its own merits because it tends to benefit white men. (https://twitter.com/JakeHerrington/status/144328685321023079...)

They quoted the start of a thread the author summarized saying it's bad because it gives cover to bad behavior. And can require people who recognize a pattern of bad behavior to persuade themselves they're paranoid. You might disagree. But those points have nothing to do with race or sex. And pointing out it's easier for people who face less bad behavior is about white men only incidentally.

I don't think it's a good idea to respond to this in depth, so I'll just say that I disagree with his assessment.