Once you get to the part about the billboards, you cross from private to public property. You’re not talking about billboards, obviously, but the public airwaves. All airwaves are essentially owned by the government and private companies pay to license them. It would be anti-democracy to allow private ownership of something we all live in. Freedom of speech is not violated when the government restricts what is essentially public roads (in the form of radio waves) for the benefit of the public.
To put it simply: it is not a violation of the First Amendment if the government, as part of its agreement to lease out public airwaves to you, regulates what can go through those airwaves. Remember that Citizens United not only decided on whether or not the movie could be shown, but whether it could be advertised through broadcasts.
I’d like to ask how you and Ibn feel about anti-electioneering laws. Over where I live, its illegal to do electioneering in the buildings of the department that handles voting in this county. It is also illegal to do so within 100 feet of a polling place. Given that polling places are usually privately owned homes, churches, or public buildings like schools and libraries, if you think your own private domain should remain so insulated from regulation, do you think people should be able to do electioneering inside their own homes if its a polling place? If its a school, should principals be able to alter the polling places to their choosing? And if a church, should the church be able to put up signs telling voters to vote for the correct candidate?
Those obviously touch upon the same issue, which is that your personal freedoms vs. the notion of equal representation in the public sphere in a democracy. The prevention of the kind of broad electioneering that the Hillary Clinton movie is not a violation of the First Amendment’s freedom of speech because it is all about abusing public entities for private gain.