I know folks don't always agree with me, surprise surprise!

However, I think I can speak to this issue.
1) Kevin nailed it here:
Feminist writers are very free about the use of the term "vagina" and it will absolutely be a different encounter when reading feminist work - especially as a male.
2) Christian pop/publishing culture is very patriarchal (much of Christianity is in general)
3) Patriarchal societies don't like women:
(a) Freely expressing sexuality that is not viewed through the lens of male sexuality
(b) Talking about vaginas and menstruation
This last point is evidenced by much of the "unclean" language surrounding women and their menstruation periods in the OT. Men don't like that stuff, and we don't like vaginas being talked about except when it has to do with reproduction, which specifically relates to our own sexuality.
Feminism is generally very frowned upon in good "Christian culture" and, when you bring in the above-mentioned considerations, it's pretty clear that the problem lies exactly with what Kevin said. She was using it in a way that simply wasn't acceptable to the patriarchal Christian publishing culture.
I have no doubts in my mind that it was sexist. Not in the least.