Do you not believe that people can stand on a public street corner and express their ideas freely, where many people will likely see and hear them? Your examples are edge cases (court rooms at midnight) that seem designed to suggest that no such places exists. They do exist, and I am asking where is there online version. Are you suggesting that the only way to exchange free speech online is for each passerby to create their own website and respond on their respective websites? I've seen people claim voter suppression for fewer hurdles. Or are you suggesting that it is the responsibility of a private entity to create and maintain a public square?
Where is the online public square? That's the point I am trying to make. And as others have pointed out, if you think having domain name and hosting is a public square, then you are ignoring all of the precedents of those things being removed by private entities.