That would be a more compelling point if the gender imbalance was confined to company founders. But it isn't: the whole industry is rife with it, both in startups and on dev teams at bigcos. Go to an F-500 bank sometime and compare the IT team with a dev team: the IT team will have many more women than the dev team will.
It's something about software development in general; it's not the fault of VCs (which I'm not a fan of either).
I think that the cultural impulses that exclude women, minorities, and older people might come mostly from on-the-ground male immaturity ("brogrammers"). But I blame the VCs for encouraging that cultural tendency instead of muting it. They're supposed to be the adults, and they fail at that.
One of the issues that software development has, I think, is the combination of hard-to-audit work with a short audit cycle. Most professionals get a couple years of work done before they're subjected to a serious, "are you capable of moving up?" audit. Lawyers are tracked for partnership or out at 4 years, which means they get a large number of chances to prove that they're partner material, and the long audit cycle takes out a lot of the noise. In software engineering, especially with the fast-firing culture, there's less time to prove oneself, and you have to start beating your chest and looking impressive before you have time to actually do something impressive. This tends to favor people with large egos, which turns a lot of women off to the industry.
It's something about software development in general; it's not the fault of VCs (which I'm not a fan of either).