I think he's pretty fair to us given how badly York screwed him.
Not only was fired when he shouldn't have been (and history certainly proves that), but the firing was handled incredibly poorly. The Yorks leaked it to the media before telling him and he only found out about it when his wife heard it on the radio. Then the told the media where the face to face would take place so that Mooch could get ambushed by reporters walking back to his car while York slipped out the back. That's just not how you treat people.
Keep in mind, football is a sport to us, but it's a business to them. If your boss screwed you over like that you wouldn't just chance your mind about him 7 years later because he had some new staff.
Mooch has every right to hold a grudge and I think he's been much more adult about things than the Yorks ever were with him.