I’d venture to suggest that there could be / have been immediate, significant, measurable and constructive outcomes if the corporate PC had immediately and properly addressed the issue when it first presented.
A simple notification to the complainer that they have no business (nor is it welcome) that they express a (meaningless) opinion about the the suitability or right of the former short term incumbent to be in the role - the positive outcome there could have been that that individual wouldn’t have moved on. As to the “people are watching you” comment, well, people are always watching so that is pretty much par for the course.
The “potential” positive outcome is listen to the disgruntled contributor, determine IF they have any valid points and then respond to them setting out the corporate consideration.
Embrace - consider - respond will (99.99% of the time) be better than….
Oppose - defend - continue…