Your argument, as I understand it, is that every space public or private should be a platform for free speech. This seems extremely broad to me. This will be a bit silly, but if interpreted literally and en extremis, it would mean the individual would have no right to get someone out of their yard yelling their political beliefs at you regardless of the time of day or night. That abortion protestors could set up photographs and hold speeches in a local diner while the individual was trying to have a quiet night out eating a dinner. That a company could lie in advertising because that was their "free speech" and to not let them lie is to abridge the free speech to the company and the individual serving as spokesperson. That a religious groups could try to convert an individual while they tried to watch a local theater play. That TV's and radios couldn't be turned off less the individual inadvertently silence someone's free speech by changing channels or turning it off.
In essence I think the kind of free speech that is never impeded by government, companies, or individuals comes with a lot of problems and little benefit. As mentioned, in our historical examples of corporate self-censorship (Hays Code, Comics Code) there were created other distribution models for things that existed outside those codes for those who chose to seek them out because that's what they wanted. The example that gets trotted out a lot regarding censorship these days are the social media companies, but there is nothing preventing distribution of ideas through other platforms (even if those platforms have to be created) if Twitter or Facebook block something.
As I said before the right to free speech does not, as I see it, also come with a right to an audience.