(1) the substance of the feedback and actionable specifics (e.g. "you didn't cite X")

(2) the actual text of the feedback (if it was given in written form)

If she was denied (1), I agree that is grossly unfair. If she was denied (2) but granted (1), I don't think that is so unreasonable. If feedback is anonymous, sharing its exact text can give away who gave it (you can often work out who wrote something just from the style of language the author used, especially if these are people you know and work closely with.)

If she was given actionable specifics ("add a cite to X"), then knowing who it came from and the exact text of it is irrelevant and I don't think she has a right to it. If she was denied actionable specifics, that is grossly unfair to her. I think one difficulty is that her account makes it sound like she was denied that, Dean's makes it sound like she wasn't, I wasn't there so I don't know whose account is more accurate.

For example suppose that Timnit was told to withdraw after an incomplete review indicates that they don't want to publish. If she asked at that time for a complete list of things to fix, nobody can give it to her because the review isn't finished. Nor can they produce it in a timely matter because it takes time to do the review.

Later the detailed feedback is ready. And if she wanted to submit the paper elsewhere, she could have fixed it and done so. But by then things have blown up and it is too late.