Is rape the only thing that companies should fire people for? A pattern of relationships like this is quite likely to be very bad for Google, both in terms of settlements and in terms of lost morale and acceptance of shitty behavior instead of working together on the great common project. The question isn't "forced" it's "why is firing the subordinate done instead of firing the habitual asshole when it's clearly in the companies interests to fire the habitual asshole." And the answer to that question makes it plausible that Google has been protecting bad people at the cost of their idealistic but achievable missions.

Also, she may have made that choice, but also he "got" her to quit - not sure if you've been in a relationship, but both things can be true. Someone can influence you to make a bad choice. The responsibility for that bad choice then exists in both people.

... because he had promised her financial support and if he also lost his job, that would go away.

And then he withdrew / refused support, that he'd agreed to, in writing.

Yes, it's not all black and white, but it's close to willfully obtuse to see a timeline of events and then fall back to a definition of "well, he didn't hold a gun to her head/use physical violence so it wasn't really a forced situation".