Ok, so we have a group of people with poor social skills. Note, people within this group can relate to oneanother much better than they can relate to people outside this group. Add to that an extremely skewed gender ratio, and you will find a lot of lonely men. Lonesomeness often leads to bitterness and misogyny. I don't imagine it's particularly pleasant to deal with someone who is both attracted to but also has a deep-seated anger towards your gender.

Add to that the usual friction you get when people with poor social skills get together, and I can see how you might have an unpleasant situation.

I've also heard it explained like this: Assume everyone wants to work (or talk about technical stuff) 95% of the time, and flirt 5% of the time. Assuming your company (or LUG) has a 1:10 female:male ratio, and furthermore postulate that all participants are hetrosexual. The women who do show up will be irritated, not because they don't want to flirt, but because they want to do other things as well.