One of the summary findings of the indictment does seem to suggest that quantity was a factor: "[The] defendant, AARON SWARTZ, knowingly and with intent to defraud, accessed a protected computer... in excess of authorized access, and by means of such conduct furthered the intended fraud".

JSTOR's salary rate is really the least of my concerns (though wasteful bureaucracy in the non-profit industry does concern me in general and tangentially relates to this story). My concern is over the US federal government pursuing felony charges when a researcher violated a website's terms of service statement. I'm sorry you received any other impression.