Let's be hypothetical here: how would you feel about this situation if Manning did do what he did back in college, but instead was more remorseful, and willing to fess up to his actions? Would you, in an unbiased vision, still be chopping away at him for it?
It's hard to be sympathetic and forgiving when he continues to cheat, lie, and attack those who are honest about him. Anyone who deliberately uses their wife to hide their transgressions is a scumbag, Peyton is a scumbag.