It's because they don't have a horse in the race. They know how hard it is to win and how much work truly goes into it. They understand that what this man has done/is doing is f-ing insane.
The NFL guys know it too. The difference is they keep losing to this man and it frustrates them. The saltiness keeps them from giving him his just due. They'd rather whine about old ghost stories, like taped walkthroughs and such. Even the f-ing Panthers, yeah the Panthers team that had a roster FULL of doped up Universal Soldiers, have had the nerve to say NE "stole" a Super Bowl from them. Cheating is now (and probably forever will be) the narrative and the losers feel comfortable with it because it somehow exonerates their ineptitude. Those who have any bit of objectivity (Big Ben, Sherman, Brees, Rodgers, and a few others) know what they are witnessing is GREATNESS, PERIOD!