Weev may not be the hero Gotham City needs, but he's the one Gotham City's stuck with. That's the thing about the judicial system; you go to court with the defendant you have.

The government may well have been counting on weev's reputation to work against him here. If your goal is to set a precedent that allows "unauthorized access" to be defined after the fact, you want a defendant people won't stand up for. It's much easier to turn bad law into bad case law when people don't fight back.