Fairness Doctrine

I want to point out that I  hate the idea of the "fairness doctrine" I believe that people on the radio and tv stations have a right to have shows that express a niche markets POV and it is a huge infringment on radio stations rights to level the playing field.

Even  though I do not always agree with people like Dr. Laura, Rush Limbaugh and Sean Hannity, there is no denying how much money they make for the companies that they work for. The advertising revenue they bring in is crazy. Liberal talk radio has been tried and failed because it simply does not work. Randi Rhodes, Sam Sedar, Al Franken and Ed Shultz cannot compete because they are all doom and gloom, depressing to listen to and do not deserve a good time slot or big fat monetary contract because they do not bring in as much money as the conservative talk radio host do.

That being said I am confused about something. From what I understand the fairness doctrine wants to mandate that both viewpoints are presented. 

Here In San Francisco Bay Area. We have a conservative radio station called KGO. I have heard a commercial that tend to run during Rush and Hannity. I'm paraphrasing here, but it goes something like this

Nancy Pelosi and her friend in congress want to reinstate the fairness doctrine and to destroy free speech, the program that you are hearing now might be danger of being removed from the airwaves and never heard from again......

I thought the point of the fairness doctrine was to present a different point of view and  mandating liberal broadcasters as well, I am not understanding how it will threaten to take somebody off the air, never to heard from again like a old horror movie.

Can someone educate me more on this topic?