I guess I look at it from the point of view, if you know something happened, and you don't do everything you can to make sure the authorities (not the Penn State Police but real cops and outsiders from the university) are involved, you failed and it overshadows everything you did.
A person can live an unbelievable life, but if you let boys be destroyed by a monster by Sandusky, and you didn't do EVERYTHING you possibly could, you deserve to have your legacy tarnished. Think about it if it was your child that was raped, and you knew Joe Pa knew something could have been up and didn't do everything.
Would you care about all those he helped or would you think more about all those he didn't? I am pretty sure you coach youth sports. No matter how many kids you taught and helped to be better men, would parents care if you didnt do everything you could to stop another coach from being a monster like Sandusky?