It is true online. It is very very true in more technical communities. As someone who's career and hobbies are/were in or very tech related I get this a LOT. There are only two small, community hobby boards in my decades online where I have not seen it last long. It still happens there. Both have small tight communities though and happily ban/run out of town anyone they decide doesn't fit. Happily harassing the rare females there annoys them enough.
I have not been at the Hive long enough to guess here. I even wonder my attempts to educate in the hacking and voter thread on tech are being dismissed in part due to my gender. But I then remember, on the internet I could be anyone. While I feel very well qualified to present the information I did, I did not, and will not post my resume. I absolutely won't post the two relatives resumes in tech/security either. And the participants may not know I am female anyway! But my impression here is important. I may get needlessly defensive. So even if no one here is dismissing me due to gender, past experiences do color my responses. I am more willing to just walk away than deal with it. In real life I'd deal with it promptly. So the defensiveness and the quick to disengage rather than even find out if this is that crap (again) is a factor.
And I will speak from experience a female. Gendered ids won't do squat. The people that want to harass women will look for cues and wait for someone to post something that discloses their gender. Since you also have to define gender it is very non-gender conformist unfriendly.
For example, fark.com before they decided to crack down on this themselves (and no they aren't one of the two private boards!) had a thing in your profile called "boobies". Once an admin guessed you were female, that field was updated to YES, with the date and a link to the post where they felt they had guessed your gender. A tad obvious no? I just looked, as I was going to link it but I guess they removed it as the site owner "grew". But for people who feel the need to know to harass they will still track, and accuse and harass. I am a very active computer gamer, just don't get me started on gamer gate. /cringe /stresshandflaps
IMHO, a sound, comprehensive anti-harassment policy that is enforced does work. But again, I've only seen weeding that aggressive on private, one owner hobby-based boards.