It is not clear at all. Nobody at Google has said that she was fired for being toxic. That’s your inference.
No company will ever say this publicly.
Yes, that's my inference.
Looking at this Twitter thread between her and Jeff Dean 6 months ago: https://twitter.com/JeffDean/status/1278571537776271360 ...
She is highly toxic, not just in general, but specifically toward Jeff Dean, who is her manager's manager. Actually, doing that against anyone is not okay.
Reading between the line, she is absolutely fired for her toxicity. This event is just a last straw.
That is the language used when firing someone for their behavior.
As per the above comment