A boss making a pass at an subordinate is not sexism. It's a big problem, yes, and it doesn't sound like Uber handled it very well if the woman's account is accurate, but there wasn't any trace of sexism throughout the entire story that I saw (I was skimming) except for the meeting with the HR woman she briefly described at the very end.
The bulk of her story seemed to be just vague conspiratorial stuff, implying her poor performance reviews under another manager on under team was due to the original boss's evil influence which... I don't know, anything's possible, but it doesn't seem like a reasonable default assumption. In the crazed and cutthroat culture she describes, it seems more reasonable to assume it was normal bullshit, not evil anti-woman bullshit.
Oh yeah, and she seemed to think that the company's refusal to order a special feminine version of the special leather jackets they had bought constitutes sexism. Just let that sink in a moment--*not* pandering to arbitrary social conventions that insist a female's jacket has to have a slightly different cut and styling is sexism. Why stop there? Why not insist it's sexism to not give all of the women hot pink keyboard, perhaps spangled with little glittery flowers?
The first step to getting people to take sexism seriously: don't conflate normal (if inappropriate) sexual advances as sexism. That's fucking stupid, and a lot of people will instantly tune you out after they realize that's what you're implying. It's only sexism if there's discrimination involved and, unfortunately for this woman, she's not describing any documented discrimination that I can see. I don't know what I'd tell her except to look up California laws on hidden audio recording, maybe. The HR woman at the very end sounded like she was saying sexist shit, but everyone else, by her own admission, had excuses for her performance evaluations.
Were they bullshit excuses? I'm sure they were. But that's par for the course for performance evaluations in a cutthroat environment; you can't just assume that it's sexism, just because a *former manager on a different team* once made a pass at you.