I very much agree with the premise but she's not a very clear writer. I think she assumes the reader already knows what the problem is.
My take is that the more people focus on identity ("female" "founder" "hacker" "HNer" whatever), the less they focus on results. Everything that happens in their lives gets viewed through this lens of identity. Unfortunately, that colors things in an unrealistic way:
"This guy trolled me because I am female" vs "this guy trolled me, and he trolls a lot of other people with penises too, because he's a dick".
It leaves you ridiculously vulnerable to identity attacks:
"Top 10 Traits of Entrepreneurs" "Are you entrepreneur enough?" "Hacker News is a wasteland" "Designers Suck At X"
Identity-involvement not only reduces your ability to see reality (you look for the first fit explanation to any occurrence, and identity is always with you), it also means you are really easy to troll and manipulate. Either by insulting or questioning YOUR identity, or massaging it and propping it up ("I have the traits of an entrepreneur! Yay!") ("Hackers will inherit the earth"), or attacking your lack of support for their identities ("Why doesn't your conference have 50% women?").
Finally, identity-involvement leads to a narrowing of experience -- "Do female founders do this? Can they? Will I be fulfilling a stereotype? Will I be letting people down?" "I'm a designer… designers don't x" "I'm a hacker, and hackers care about the hottest technologies…"
It becomes about grooming, enforcing, and defending an image, rather than results.
I see this a lot. It's a shame. I used to fall prey to it myself, wishing I wasn't a woman because of people thought "woman" meant -- something I had no interest in (hair, makeup, purses, women's magazines, women's meetups etc) -- and those other women "made me look bad".
But then I realized what an ego trip that was. "Woman," too, is just a label, and by denying it, I was implicitly buying into its legitimacy.
Now I just do whatever the fuck "Amy" does, which is my stereotyped identity sample size 1.
A friend of mine was concerned that her girly clothes and love of makeup make her less credible as a spokesperson for women's issues. One of these seems like a concern about sexism… but both hers and my worries are actually about the same issue (identity). Like me, my friend also has learned to simply embrace who she is and not worry that she's "letting other women down" by simply doing what she loves.
It sounds to me that this is what the author is getting at, she just doesn't lay it out that clearly. That's why she says things about women's symposiums, talking about femaleness, etc., stressing about / regretting (instead of using) the fact that you're the sole female in a thing[1], because those are identity involvements. These points of hers, I agree with.
To those who will say that she is saying "act like a man" -- she doesn't.
To those who will say "this is glossing over very real sexism" -- please see my example above about the troll. Often people assume that if something is (OR APPEARS to be) sexually related, it's sexism. They look at the first possible answer ("she's being trolled… she's a woman… it must be because she's a woman!"). But 9 times out of 10, the guy who insults a speaker for being a woman, insults another speaker for using JavaScript or being fat or wearing a suit, or looking like a hipster. That's not sexism, that's an equal opportunity dick, who simply seizes on the most vulnerable part of his victim's identity. Yes, identity.
Is there real sexism? Absolutely. But is there any proof that women's conferences and angry blog posts help?
Sure, it's annoying for some dude at a meetup to assume you're there with somebody else. It's also annoying for some woman on Twitter to loop me into "sexist technology" rants because I have breasts and therefore she expects I agree with her. But that's just life. You can't control what people think, not even of you. And the annoying people in both examples are just pattern matching, which usually works, and not making a value judgment about your person (aka sexism).
[1] (Aside: stressing about being "the only x" in an environment is often even more about identity-confirmation -- I need other people Who Look/Think/Act Like Me to validate my choices are okay -- as it is about exclusion. This is the same reason some people love being "the only x" -- it confirms their identity as a renegade. Also, "the only x" is often not about physical facts (sex) but also about viewpoints.)