If your team of ethicists has repeatedly highlighted issues and you continue to not address them, what should they do then? In the case of a company whose self-image is of openness and directness and benevolence, it seems reasonable that publicly highlight the lack of change is within reason.
If they cared less, they'd just shut up, but employees seem to have a higher opinion of Google than Google does of them.
Firing them in the middle of that suggests an unwillingness to deal with the previous issues, doubling down on unethical behavior.