He violated Terms of Service for a large database of journals at an egregious rate. If he had stolen say...10,000 articles this may be a non-issue. The fact that they can tie 4,000,000 articles to him is what makes this so bad.

The other part that is extremely bad is his measure to continually evade MIT MAC banning through spoofing. That measure of evasion proves, to some extent, his intent to steal and is a form of computer fraud.