Google (and Google Brain in particular) benefited immensely from Gebru's work, and her being affiliated with them. This can be seen in how often they (including Jeff Dean) pointed to her work to show they were taking questions of fairness and bias in AI algorithms seriously.
The flip side is that you have to respect the researcher, who frankly has more credibility than you do as an organization in this space.
Even to corporate researchers, demanding (through an HR procedure? bizarre) the researchers retract a paper without a discussion or an opportunity to revise it (which is still possible since the paper is only in review!) is highly unusual. To do that to a researcher whose work you loudly (and seemingly proudly) advertise, is insulting to them and the broader team they hired. And to do it over not citing literature? Unheard of and clearly indicative of something else going on. This seems like some kind of turf war.
You can read the abstract of the paper in question here - it is incredibly anodyne, though obviously does take a critical view of Google Brain's work (BERT in particular); https://www.reddit.com/r/MachineLearning/comments/k69eq0/n_t...