I am, gasp, a female software engineer. I work at a defense contractor, and I'm thankful to say that every year there are fewer fossils who think that women don't belong in software, let alone working on military software. The hostile environment is sometimes present in subtle ways, such as important discussions that occur spontaneously in the men's restroom or cubicle artwork that borders on inappropriate. Or, of course, trying to get projects assigned to other, male, engineers. Heck, I once heard a co-worker complain that he would have gotten his promotion if he's been a woman, with an obvious implication since I had gotten mine - ignoring that I've worked here three years longer, am considered more helpful and, oh yeah, _trained him_ when he got here. Nope, obviously, it's because I'm a woman.
Anyway, Slashdot is a perfect example of said hostile environment, from the subtle ("You're joking, there aren't any women on the internet!") to the cesspit that the discussion turns into whenever the topic comes up. I'm sick of it, frankly, and I really should just stop bothering to read the comments on most stories, causing me to lose out on the occasional insightful nugget, but helping my blood pressure. Someday, it might even be bad enough to drive me away.
Which was my point. Telling someone that they are imagining there is a problem is highly offensive, really, and tends to make people not want to be around you.