I'm surprised that HR was immediately on the manager's side. I'd expect HR to protect/defend management that is above their work group, they write the checks after all. However, there is no incentive to protect anyone on the same level or below their reporting manager.

HR exists to defend against litigation and conspiring with Kivin's manager worked directly against that purpose. Their actions resulted in a fat public lawsuit where winning won't matter. The findings related to the ethics of Amazon's ad platform are damning, their corporate customers would love to recoup misappropriated advertising dollars with their army of attorneys on retainer.