The government-owened airwaves shouldn't provide a "forum" for anyone. They should be privatized. I realize that adoption of private property is strange concept to the people who love the idea of "public" contol, however.
The thing you want to privatize and broadcast porn on is the air and its associated frequencies that pass through my private property.
Very few things should be public; the roads in front of my house, the military and our Constitutional form of government are three things that quickly come to mind. The air that passes through my private property is another.
It isn't your unalienable right to load the air up from your property with pollution and send it over to my house and it isn't your unalienable right to load the air frequencies from your private broadcast facility and send it over to my house.
It is you who loves the idea of the "public" distribution of porn on something that is so public, so basic and so low in viscosity -- our air.
Go get your porn from a private medium and quit relying on the resources that aren't your own private property to view it.