I agree, they should be fired, but being in the cockpit while over the limit is not a crime. The judge is counting on them not having the cash to appeal.
It isn't illegal to sit in your car, in the driver's seat, with the engine off if you're drunk, either. But the moment you turn the engine on, you've broken the law---even if you haven't yet taken it out of park. The difference is of course that you have begun the necessary process to drive; you are "operating" the vehicle.
Driving a plane, particularly a commercial jet, is not a matter of sitting in the seat and turning the key. The process of "operation" begins long before taxi or takeoff. It even begins before the engines themselves start. And the entire process requires command of your mental faculties.
So no, I doubt this will get overturned on appeal.