These laws were passed because they were seen as better than the status quo, which was employers firebombing their employees or highering mecenaries to shoot them.
They didn't even fire her. Apparently they just said, We don't want you involved in the AI ethics discussion going forward. That seems reasonable, considering her past efforts in that area have not benefited Google in any way, but rather harmed them.
Just as employers can't firebomb their employees for organizing, employees can't bury steel spikes in logs headed for the sawmill.
That assumes some humility and objectiveness from her higher-ups. "Oh you publicly criticized our project, behind which some of us have staked our reputation. And you created a major negative PR event as well. Thank you for that! We finally see our mistake and we'll apologize and move on". In some hypothetical rational universe it might play out like that, but in reality I don't see how that was supposed to turn out without some repercussions for her.
The questions involved have to do with should we build this tech, not how to build this tech. To argue otherwise means that the vast majority of people should not be allowed to have opinions on the ethics of nuclear weapons, medical procedures, or any other topic where they are not subject matter experts.
AI tech and the ethics of using it is rightly a political topic, since it has the potential to affect everyone on the planet.
Preemptively saying that certain viewpoints have no place at the table simply means the political discussion will move from a friendlier environment within Google to the (likely more hostile to Google's interests) environment of general politics in the U.S. Personally I think that might be a better outcome, but from Google's standpoint it's potentially a disaster since it might result in heavy regulation of their business.
The idea was to have some people from outside the company look at the tech and its potential hazards and provide some input on the ethics of developing and deploying it. People inside the company said, No, we don't want that particular viewpoint to be have a seat at the table on this outside committee. The ethics panel had nothing at all to do with their working conditions.
Did we not, uh, already have laws against firebombing or hiring hitpersons? I would have thought these kinds of rights-to-collective-action laws are more about employers just summarily sacking people who do things that they're legally entitled to do but that are politically disadvantageous to their employers.