Broadcast bandwidth is a limited resource, so it’s subject to special rules to ensure it’s fairly distributed in the public interest. It’s true that the rules aren’t nearly as important as they were when non-broadcast news was harder to find, although that doesn’t give the criminals in charge of the FCC a right to ignore the law.

The FCC mainly regulates broadcast. CNN is cable. Also, there's a difference between a station being in more than 39% of households and being 39% of the total market. Other stations still compete with CNN.

This is about over-the-air/broadcast stations (e.g., ABC/NBC/CBS affiliates), not cable stations like CNN.