Yes, Google’s ethical responsibility in a current employer/employee relationship with Mitchell is different than Gebru’s ethical obligation to her former employer with whom she is already in a public, contentious battle.
And even if the ethical obligations were identical, Gebru’s violation toward Google wouldn’t excuse Google’s toward Mitchell.
If we accept Google's own claims, they have an automated indication which leads to suspicion of that and on ongoing investigation, not even something where they are prepared to claim an actual violation. i.e., exactly the circumstances where every half competent organization would decline comment (potentially citing “personnel matters” until they'd actually completed an investigation.)
So you say you suspect they have an ongoing investigation, and that would be "circumstances where every half competent organization would decline comment"
What substantiates this conclusion? They can have an investigation ongoing, and share the cause for said investigation. In the statement they explicitly establish that this doesn't imply guilt of the account owner.
Yes, Google’s ethical responsibility in a current employer/employee relationship with Mitchell is different than Gebru’s ethical obligation to her former employer with whom she is already in a public, contentious battle.
And even if the ethical obligations were identical, Gebru’s violation toward Google wouldn’t excuse Google’s toward Mitchell.