The internet, as a whole, is the public square. The "common carriers" that have nearly no limits on what you're saying (As long as it's not hacking/spamming) provide the access, but if you and a website don't get along, that's that, you can always start your own (/me looks at babka.social )
People complain that this is a high bar for entry. On the contrary, it's a lower bar of entry than it used to be, where if a publishing house wouldn't print your flyer, you had to build and learn to use a press.