The public square is alive. There are people in my downtown right now with megaphones uttering their own flavor of insanity. You also have more reach than ever before in human history thanks to the fact that anyone can pay a few bucks a month and set up their own website with their own rules.
And the right to free speech has nothing to do with you getting your ideas heard. It's everything to do with what you can and can't be prosecuted for, and therefore is irrelevant when we are talking about something like youtube which can't prosecute you in the first place. Even back then the law could have said something like everyone has a right to get their essay published in the newspaper, but it didn't, because you can imagine how that would quickly get ridiculous, and ultimately just like youtube newspapers were private entities, only they had even more influence and reach than youtube since everyone read them and took them seriously as the paper of record.
And the right to free speech has nothing to do with you getting your ideas heard. It's everything to do with what you can and can't be prosecuted for, and therefore is irrelevant when we are talking about something like youtube which can't prosecute you in the first place. Even back then the law could have said something like everyone has a right to get their essay published in the newspaper, but it didn't, because you can imagine how that would quickly get ridiculous, and ultimately just like youtube newspapers were private entities, only they had even more influence and reach than youtube since everyone read them and took them seriously as the paper of record.