Perhaps you're technically right, but she claims to have it documented, and has already shared it as per her tale in her HR efforts. The NYTimes would not likely publish nor Kalanick contritely move to investigate so thoroughly if it were so easy to repudiate her claims as hearsay. We'll know in short order as the company rushes to save face.
Obviously. She's presented her personal story in the form of a blog post - we're all well aware of that. And it seems you're perfectly willing to accept that story up to the point that it matches your preferred narrative (ie. "bad shit happened, couple of morons"), but anything more and it's "where's the proof?!"
Why not just call her a liar and show your real true colors?
It's not good to conflate healthy skepticism with the belief that one is an outright liar. We know so much about the fallibility of memory and how bias affects recounts of events these days.
If somebody with "hate" in their name responds to credible accusations of sexual malfeasance with false interjections of "but there's no proof", then we're already approaching Fox-News-comments levels of quality.
If you aren't claiming that ultrahate is displaying healthy skepticism, then what do you think he's doing? And why is that valuable enough that you took time to defend it?