Not only does he make the logical fallacies you suggest, but he also ignores plenty of evidence that there might be natural causes:
For instance, there is plenty of evidence women are less likely to be very good (or very bad) at math: http://www.sciencemag.org/content/321/5888/494.summary http://www.ncbi.nlm.nih.gov/pubmed/21038941
There is also evidence women are more risk averse, making them less likely to work in startups: http://www.pnas.org/content/106/36/15268.full
There is evidence women avoid computing specifically because they are intolerant of geeks: http://web.archive.org/web/20100106021904/http://scicom.ucsc... (The original article was taken down)
This report also pushes the intolerance hypothesis, as well as women being less dedicated, being fearful of text interfaces, and preferring more collectivist environments: http://web.archive.org/web/20091007234852/http://opensource.... (Please go read the report before criticizing me for citing it. It's written by a woman who is allegedly a feminist.)
It's safe to say that none of this is ironclad proof that the only cause of women not being present in computing is natural causes. But the author's claims that "there's no such evidence" is utterly wrong. There is evidence, he just ignores it.
Lastly, the author completely ignores the fact that computing is very diverse. We have whites, all different types of asians, israelis and a smattering of euros (and of all sexual orientations). Our diversity may not be statistically identical to the general US population, but it's nonsensical to claim a lack of diversity in computing.