From reading the article it is pretty clear that the decision to let him go was already made months before. So what's the point?
An exec that cannot deal with (polite) disagreement is probably on the way downwards already himself. Of course you might hit a sensible spot with honesty by chance but even then it is hard to justify an otherwise successful employee.
I've wondered if Sullivan set up the bomb on Sculley, basically daring him to fire Jean-Louis. Sculley is a lose cannon that fires anyone that gives him needed feedback. Jean-Louis is important enough that firing him will bring that into sharp relief.
Sculley fires Jean-Louis, the resulting blowback doesn't convince Sculley of anything and Sculley is too dumb to know he needs to leave. So two years later the board is forced to can him.
An exec that cannot deal with (polite) disagreement is probably on the way downwards already himself. Of course you might hit a sensible spot with honesty by chance but even then it is hard to justify an otherwise successful employee.