You're focusing on the grand jury presentment which solely addressed the charges against the administrators and Sandusky. That presentment said nothing about what Paterno did beyond going to his "superiors." That doesn't mean, however, that he did nothing. The state AG in fact commended Paterno in that presentment. But for what? That's the key question.
We didn't know until the unauthorized release of someof the pretrial testimony. Paterno went to the campus head of police weeks later and was livid at the lack of an investigation. This will all come out in court. Among other things revealed is that the campus head of police was given the child's name by Sandusky and the kid was interviewed by Schultz (the head). Like all the kids Sandusky molested, the kid initally declined to say anything. Read the article below which shows that all the victims were reluctant to come forward except victim #1 (the high school kid molested in 2008).
In addition, though I was willing to cut McQueary a lot of slack earlier, it may be that he did not reveal the extent of what he saw. His friends said as much when he spoke to them the night of the molestation. They said he described nothing like what was in the presentment.
The take in many Pennsylvania circles is that the PSU people certainly screwed up in 2002 but that there wasn't a concerted effort at a cover-up. Look at what they did in 1998 when they brought state and local authorities into the investigation. Back then, Sandusky was still a coach. If they were willing to investigate back then, why not in 2002 when he was no longer a coach? If they were covering up to protect the program in 2002, why not in 1998 when they launched an investigation? Read the link in the article below if you're interested in more info. You'll find that the state didn't have much interest in investigating either. Many suspect the full scale investigation was launched because of the governor's fight with the PSU President, and that Paterno was collateral damage as the governor was trying to put heat on the President. In that article you'll find it was the parents who suggested the investigators look in logical places (like Sandusky's book) and also, only PSU retained info about the 1998 investigation. The local police and state authorities had no record of the investigation.
Jerry Sandusky's book, 'Touched,' helped police investigation into alleged sex crimes | PennLive.com