As the article explains, the concern is that they violated a law originally designed to prevent malicious "hacking" and that carries penalties that may be stronger than are warranted for something that's a lot closer to trespassing.

If you scroll past the first few pages, you can read the EFF explain in detail why this is a problem http://ia601209.us.archive.org/33/items/gov.uscourts.cand.25...