The government, to some extent, considers local network providers as a service to their community. They require records, for example, of certain amounts of public service broadcasting. Also, in times of, for example, severe weather, the locals are considered to be of great service to the community.
The simple answer is that Congress should step up and say, here's the arbitration process, everyone has to follow it, and local networks cannot be removed from the air during this process. But - politics/lobbyists/etc.