Facebook, YouTube, and Twitter also have as their primary purpose the propagation of information and messages by and among their users. It's not some incidental

Facebook, YouTube, and Twitter also have as their primary purpose the propagation of information and messages by and among their users. It's not some incidental or secondary feature. It's what they do. And they promote this to the public with almost zero barrier to entry. Yes they are still private entities, but like a hotel that is open to the public, they become constrained in the restrictions they can impose since they have chosen to be in that business.