>Then the correct way to handle it is to drop another refutational evidence bomb attacking his primary points instead of picking the low hanging fruit of claiming it's "too confrontational," "poorly written," "naive," or whatever other secondary problems exist (this is aside from wilfully misrepresenting his claims, which is definitely a bigger problem).
The brute problem is that it's too long to be addressed in a reasonable and productive debate, and because it was posted on an internal company messageboard it is his responsibility to ensure that it can be responded to in a reasonable and productive way. If he presents his complaints in a format which is likely to cause problems, he can be penalized, and a manifesto is certainly such a format because it lends itself so well to "viral" sharing, and it was precisely such "viral" reposting of the document that made it a practical problem for Google in the first place. Had he made his points in an ordinary discussion thread, it would have been harder to publish it everywhere as a unified whole, since discussion threads by their nature will contain counterarguments.
For example, if I think another employee is biased against me in code reviews, it does not do me any favors to write a multi-page manifesto indicting said employee on a variety of points for his/her alleged biased review practices. Good debates do not generally come from duelling essays, and it is unfair to participants -- practically unfair, in that it drives them from the debate and so deprives the conversation of their contributions -- it is unfair to participants who do not have the time to invest in researching every point of a ten-page document that they feel they must address the whole awful thing in order to say anything. In fact I try to limit the length of my HN comments for this very reason: long comments are hard to respond to well.
Internal company messageboards do not lend themselves to the publication of manifestos, and it is not reasonable to expect them to.