The FCC's Fairness Doctrine didn't apply to newspaper because in theory, there wasn't a limit to the number of people who could publish a newspaper if they wanted to.
The Fairness Doctrine had two basic elements: broadcasters had to devote part of their airtime to the discussion of controversial issues of general interest, and disseminate the different points of view on these issues. Channels and radio stations had a great deal of latitude in providing these contrasting views: this could be done through news bulletins, public affairs programs, or editorials. The doctrine did not require equal air time for each point of view, but the presentation of these different points of view.
The main purpose of this doctrine was to ensure that viewers have access to a plurality of viewpoints. In 1969, the United States Supreme Court confirmed the general right of the FCC to enforce this principle of impartiality where channels were limited. But the courts have not ruled that the FCC was obliged to do so. The court reasoned its opinion by the fact that the scarcity of the spectrum of diffusion, which limited the possibilities of access to the waves, generated the necessity of such a principle. However, the proliferation of cable television, cable channels, public access channels, and the Internet have eroded this argument, due to the multiplicity of sites allowing the ordinary citizen to make public comments on controversial issues at a low or no cost.