“When speech got digitized, the town square got privatized and the First Amendment got euthanized. If you can’t speak online... how do you really have a free speech right in this country any more?”
The "town square" didn't get privatized because FB/ Twitter/ etc. never belonged to "the town" in the first place.. Being open to the public doesn't mean the public has a right to decide the policies and rules. If the public does not like the policies and rules, nothing forces them to use the service, or go to the website, or visit the venue in question.