What exactly did Joe Paterno do wrong?

I admit I don’t know much about this, but what I have heard bothers me.
He’s a famous guy somehow involved in a child molesting case, but he didn’t do the molesting. Someone else saw it, and reported it to him. He then reported it to the College Board, as I understand it.
He didn’t call the cops, but he didn’t just let it drop. He did what the other guy did: report it to his superiors.
Why is he getting shit on here? Is it because he is famous?