I understand why the optics might be bad. For me, having been in HR for 4 decades and even thought I have quite a cynical view of the ways organizations behave, I guess I have a different perception of what probably went on. What is out there smacks of people with a very specific agenda. I'm not defending what happened, just questioning the accuracy of the reporting.
Based on the reports that his role has been diminishing for a few years to the point were he was primarily a writer, the narrative I would question is that Heisler was unceremoniously and abruptly tossed, sort of some significant financial milestone that ND denied him. I would suspect that, as in many organizations where good people are spared termination until long after they probably should have been because they are good people, this was long in coming and he wasn't as surprised as some people want to paint it.