Insofar as you are representing the Rust community via HN, you've given an overwhelming impression that the Rust community is an unpleasant place where "outsiders" are totally unwelcome. As someone who considered adopting Rust prior to reading your post, that's a problem because with such an immature language I would eventually have to interact with that community and then I would apparently have to deal with people randomly nitpicking which dialect of English I learned and calling me an asshole. No thanks, life is too short.
Also you missed the point of that exchange, you are excluded from the Rust community, only if you act against Code of Conduct actively. The titular bad example was given a warning, he disregarded it several times and continued to behave against community wishes.
What do you expect happens once you act against what other members of the club urge you not to do? A single mistake/slip up isn't a problem. Repeated offense and disregard of CoC is.
Usually the custom is to greet each other with "Hi Rustaceans". It's gender neutral and has no negative connotation.
If this gives you impression of a treehouse filled with cultist, who am I to judge.
Carefree? Mostly. Non-sensitive? Pretty much the opposite. Rust community is extremely sensitive. The rules are lax, but they draw the line at making contributors uncomfortable.
In IRC, the poop jokes and calling people guys, would have the same chance of drawing ire, which isn't huge. The whole "guys" thing is just a smidge more likely to draw ire. However if you are insistent on either accounts expect to get ostracized.
> I guess they don't feel like they belong in any part of mixed gender society then, since it is so widespread.
Well, yes. It's not like women make on average less than their male peers.
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Let me show an abriged version of what usually happens in IRC.