HR wouldn't have made the final decision here, it seems other departments did. HR was just how someone felt it was safe to communicate that feedback, which for me is a major issue in a workplace.
That's just not the same as giving scientific feedback in the review process for research and shouldn't be in the way there.
Someone thought they HAD to goto HR to provide the feedback because no other way was safe. If you want to act about the scientifc review process, that should never happen and when it does there should be serious action taken.
Also, it's strange to be giving google so much benefit of the doubt here. On the same day this happened the NLRB filed two formal complaints against google for retaliatory firing practices. If any participant in this drama has a known record of retaliatory and unfair labor practices, it is google, as documented by the federal government's extremely detailed complaint.