Go up to your mother and tell her a story that involves someone breaking into restricted closet at MIT, plugging into their network, evading electronic attempts to stop him, and downloading millions of scientific articles that normally are sold for a fee. If your mother is anything like mine, she won't be able to fathom why anyone would do something like this unless he were up to no good.
Swartz did not innocuously do anything. He willfully violated laws designed to proscribe exactly the conduct he was engaged in, conduct that to your average person smacks of criminal activity. Legislators, who think more like my mother than they think like you or me, intended to prohibit Swartz's exact conduct. The prosecutor here was doing exactly what my mother or my Congressman would consider the right course of action in such a situation.
At the end of the day you have to tackle the real problem, which is this: my mother understands the difference between joy riding and grand theft auto. That's within the wheel house of her experience. People interested in "information freedom" or even just proportionate punishment in these situations need to be able to make a case to my mom about why downloading JSTOR articles on MIT's network isn't the same thing as hacking into Bank of America's servers to steal credit card numbers.