Well there are a few factors which make this situation different. If the ultimatum had been made in person, I'd think there might be room for negotiation, depending on the relationship between manager and subordinate.
Putting the ultimatum in e-mail form really raises the stakes, because there may be other people CC-ed or BCC-ed, and any response could later be weaponized.
If the relationship was already troubled, anything like an ultimatum is an opportunity for the manager to be rid of all their troubles.
The level of the threat also comes into play, and more severe threats increase the risk/tension. If the guardian had threatened to disown the child rather than send them to bed, we would read the situation differently.
I agree. An ultimatum given in an e-mail is more difficult to treat as a negotiation tactic, and it seems like there is much more to this story than we will ever know.
They way this was handled doesn't make any of the involved parties look good.
Her description, quoted from a Wired article which she has re-tweeted (which I interpret as an endorsement) is as follows:
"Tuesday Gebru emailed back offering a deal: If she received a full explanation of what happened, and the research team met with management to agree on a process for fair handling of future research, she would remove her name from the paper. If not, she would arrange to depart the company at a later date, leaving her free to publish the paper without the company’s affiliation."
