Even if that were the case and the Cayuga is a flying legal-aid clinic it doesn’t make much sense to put the lawyer in charge. You’d have a regular command officer trained to fly spaceships running the ship, and Batel would be like the chief counsel or whatever aboard. But they also did it weird with Crusher too when they made her the captain of a hospital ship. Again, you’d have a ship-captain-type-person flying the thing, and a doctor in charge of the doctoring