Again, reasonable for her to be fired.
The NLRB is where decisions like this are argued. They weighed the evidence, with a much fuller view than any of us here, and came to the conclusion that the firing was illegal.
Also it seems reasonable to me her complaint that this hurt her reputation, after all you're a Google employee and here you are smearing her in a public board. I know you're gonna say "I don't speak for my company", to which I will reply: It seems you're a Google employee, and you're speaking as a Google employee. It's distasteful that a Google employee find the need to accuse her in public like this. Is that a view shared by your co-workers? Do you all usually go in public boards to speak ill of past employees? To reveal why they were fired?
Honestly, the fact that she has the gall to complain to the NLRB about this firing is pretty despicable. Google should be suing her for defamation.
This is such an ill-informed understanding of how labor law works I'm not sure where to even start. You have a legal right to assert your legal rights, as was done here. The NLRB is akin to a trial court that makes the determination and issues judgements.
Winning a legal case is not "defamation".
I doubt that Google spontaneously published the reason for the firing. AFAICT, the former employees went to the press following their firing, and the "violation of security policies" explanation was the response to articles initiated by the former employees. It's not clear to me how the parent's comments are a smear, unless the statement that "she bypassed restriction in our code change system" is not factual (which I don't know, but I have no reason to doubt it).
[Googler, opinions my own]
This is not true. The code changes in question were done normally. The policy "exemptions" were in regard to the rollout of the resulting binary, which are well described here[0].
What more was she meant to do?
She didn't bypass anything.