Private businesses should not be forced by the government to provide services to anyone, right? This is a free public service announcement, not an ad, and Reagan killed the Fairness Doctrine that at one time required broadcasters to give equal time to all sides.
We chose freedom, this is a consequence of that choice.
If that were true, then they could reject political adds from one candidate to favor another. I know for a fact they have to provide equal access. My wife sales ad time for a cable provider.