An ideal HR department would not yield to ultimatums unless they felt that not yielding is a sound, ethical orientation. Thus, a trained ethicist's position ought to be at least tentatively considered without rushing to a decision.

The question isn't really about whether she was qualified to make ultimatums. She's not an idiot - she knew that there was little chance of it going well for her, career-wise, when she did so. Everyone who's saying "She should have expected to lose her job" is missing that she did.

The question is why she felt she needed to make one anyway.

In particular, she was hired into effectively an adversarial role: to note when Google was engaging in unethical practices. This is not particularly uncommon in business: internal audit teams do this in their own way, for instance. Or security teams, or legal teams, or whoever. All of them have the job of occasionally telling the company "Don't do this."

If an internal auditor (or security engineer, or counsel) says, I feel like I am unable to do my job under the terms you've set and if you don't change those terms I see no choice but to leave, it's worth asking why. It's possible that the auditor has an unreasonable view of how to do their job. But it's also entirely possible that the company is intentionally preventing the auditor from being able to do their job because they have something they don't want seen, that upper management wants to do something that they know their audit team won't agree with.

An ethicist is much the same.

It would be one thing if she was fired by her boss. She was not, and her boss was blindsided. She was fired by her skip-boss on the orders of her skip-skip-boss, neither of whom are on the ethics team, but who are in the larger Google AI organizational unit.

An internal auditor is usually held to some standard of confidentiality. Audit results becoming public should not happen at the decision of just the auditor (except of course if there were a legal obligation to report). In that respect she proved untrustworthy for the company by her ultimatum. She basically proved that she would be willing to make Google look bad in the future. She also went public, making Google look bad in the present. Basically the same reason for letting her go as with Damore.

She already had formal approval for her publication to be public well before the ultimatum. The ultimatum was in response to management saying "Actually, we're going to change the process on you because we find this work embarrassing." She did not make a decision to publish on her own.

Moreover, she's not an auditor, and she has never been accused of publishing confidential information. My story about an auditor was an analogy.