Having seen this happen in a number of internet communities, where women have described the reasons they would no longer visit, and having watched these communities change from reasonably well represented by both sexes to almost exclusively male-only: yes. It's almost certainly because the community at HN is offensive and exclusionary towards women.

This seems to be something of a hot button issue within the community at the moment, probably spurred on by pg's comments taken out of context, but the last few threads on similar topics have been filled with bile, reverse sexism claims, and general attacks against women. It's sad to see, because at this stage it's essentially too late for this place. The last community community I was (and still am) a part of made a conscious effort to change its moderation and terms of use to be more inclusive and punish individuals who stepped over the lines, but it was too late for them too - the sense of community was already destroyed for most of the visibly female members there. I haven't noticed them come back.