I just find it strange to focus on the very subjective whether or not the "demands" of an employee are reasonable, rather than the far more objective "Is this an explicit resignation".
To the company, every demand is unreasonable...
And every negotiation/collective bargaining begins with overstated demands, that's hardly unusual.
Sometimes things aren't that grey area in reasonableness and acceptable behavior.
I like my comparison in another comment: Having an affair and getting caught is not literally filing for divorce.
More like storming in and demanding "either you give me root access to all systems, and the building to myself, and a promotion, or i quit!"
It's a grey area, and I agree there are cases that are not de facto resignations.
But Gebru's demands were absolutely not of the compromising kind. She was effectively demanding dictator powers.
And if "i can't do my job if i can't run the company". Well... I guess you can't do you job, then, according to yourself.