get from this is not anything wrong with geeks who happen to be girls--but rather just how insecure so many men are in their sexuality (or perhaps more accurately, insecure about others' perceptions
of their sexuality). It is not perceived, in our society, as degrading the femininity of women for them to have "masculine" interests. But for a man to have any interest that happens to overlap with those of a woman...society immediately starts throwing around sexual slurs as though a) that guy can't be straight and b) if he isn't there's something wrong with him.
(Yeah, I know there are sometimes instances where women will get the same treatment, being accused of being lesbians because of "masculine" interests. But as a whole, I would say women are much less hung up about their sexuality, and more secure in it and accepting of others--whether gay or straight--than men.)
Add to that that you have more than a fair share of those who are generally insecure or immature socially, in the geek community, and it's not surprising to think that some of those insecure men would react as though it's territorial encroachment, for a woman to hold a combination of "geek" interests and "stereotypically female" interests.