"If he didn't think he was committing a crime why did he attempt to conceal his identity?"
I did not say that he thought he was doing something entirely legal, I said that he probably only expected a civil case for his actions, which is entirely reasonable. If I had to guess, I would say that whatever attempt he made to conceal his identity was done to ensure that he would not face a court order to stop until he had finished what he had set out to do.
If you are saying that concealing one's identity is evidence that a person is doing something criminal, then you are accusing a good friend of mine of being a criminal. He used proxy servers to download large numbers of patents, as part of his masters thesis project, to avoid bandwidth restrictions imposed by servers. In the end, he developed a system that helps locate patents, and could help people avoid violating patents or find prior art. Should he face a 50 year sentence too?
"If he had been accessing student's personal info, would you still be defending him?"
He did nothing even remotely similar to that. His actions were as close to accessing private information as posting to HN.
"Unauthorized access is unauthorized access."
His accessing was not unauthorized. MIT's network is open to the public, and JSTOR's archive is open to anyone on MIT's network. What access was unauthorized in this case?