Not to excuse any one's behavior, because what has happened is appalling. Just want to speak about the academic culture.
Academia is a very strange place that has very little in common with reality. There is a very definite hierarchy and a distinct chain of command. Everything you do must go through that chain of command. It is built into the culture that once you have sent something up the ladder, your job is done. If you have spent the bulk of your career in that environment and have never worked outside of academia, it might not occur to you to move outside of that chain of command. Is that right? Of course not. It is a world with a very narrow vision and zero grasp of reality.
There is also an atmosphere of fear at work, especially for the guy that was a graduate assistant. That guy at that point was in a very tenuous position career-wise. There is no whistle blower protection in place in academia. They will say that there is, but so much of promotion and tenure is nebulous and popularity based that junior faculty members are pretty much held hostage to what senior faculty want. Graduate students are in an even worse place. The completion of their degree, their job and their future is all based on what the senior faculty think about them. In this case the graduate student saw a VERY powerful supervisor doing something inconceivable. He clearly didn't know what to do about it and asked his father. His father told him to tell Paterno, the highest boss the kid had. He did that. In academia land that is the end of what the kid can do. Pushing outside of this chain of command would have meant he lost his job and his degree. Much of that world is a hostile working environment. I'm sure the grad student did all that he thought he could do.
Now, do we wish that he had been brave enough and strong enough to speak up louder and to the police. Yes, of course. Should Paterno have spoken up louder and to the police? Yes, of course. Should he have fired the coach doing the evil deeds? He** yes. Ultimately the blame should run up and down the ladder of hierarchy. The president and Paterno should have lost their jobs and possibly should be prosecuted as accessories. The guy that witnessed it all will likely lose his job. I just hope we don't vilify him and forget the guy that did the deed and those that were in a position of leadership over them both.