Here's the thing: If you had ever taken even a few minutes to sit down with women who work in our industry and asked them if anything like this has ever happened to them you would learn it is extremely common. You would also learn that women rarely get the benefit of the doubt in these situations and are often punished or eventually forced out of the company. Women don't talk about it because jerks immediately start screaming "WHERES THE EVIDENCE?!?!?!?!". As far as anyone can tell she has no interest in pursuing a legal case; in that sense this is just like the NFL national anthem controversy. No matter how blandly and inoffensively someone behaves there will be assholes at the ready to condemn them for speaking out about anything in any form whatsoever. Susan kept her head down, tried to do good work, then left for another job. She has made the absolutely minimum of an issue out of this as it is possible to make.
Try this thought experiment: assume the original story was written by a man and was identical except for the sexual harassment part. The same tales of toxic work culture. The same stories about managers protecting fiefdoms, undermining each other, and withholding information. The same story about being denied a transfer so this person could serve as a "feather in the cap" of the manager denying the transfer. Would you still be out here claiming it is the end of civil society that everyone isn't demanding evidence before rushing to judgement?
Hint: we've had these kinds of stories show up before with male authors and the answer is no, people aren't so demanding. Only people who experience sexual harassment are held to this double-standard.
Nothing about what Susan posted seems far-fetched or out of the ordinary. HR exists to protect the company from you, not to help you or ensure justice is served. Telling people this is someone's first offense is likely to diffuse the situation and ensure no one files any pesky complaints with commissions nor hires a lawyer. Playing games with performance reviews is par for the course. Anyone who complains is viewed as a troublemaker. This happens on a daily basis in most companies in the USA.
Of course I don't believe you (or the rest of your compatriots) posting here are acting in good faith. If she shared screenshots and emails you'd just claim they were faked. How exactly she is supposed to gather evidence (when CA is a two-party state, so recording the conversations secretly would be illegal) is never explained.