Differing points of view. The UK model where you can stand in Hyde Park and speak your mind spread to speakers corners in many places.
https://en.wikipedia.org/wiki/Speakers%27_Corner
You could speak, and it could be written down and hit the papers, where you were interviewed and reported - by an announcer/reporter.Then comes Radio - again a reporter/announcer, same with TV. In other words a chain of accountability where you could be assessed, and if deemed a criminal incitement there was accountability. Then the Internet and cellular message services, and you could become widely spread in an instant - your words beyond recall, and often anonymous. Even if they wanted to arrest you - they had no connection to you. They could kill your handle, and you could get another throwaway 100 times/day. You can get 100 lined up, with innocent handles and use each one once. We see how some countries completely shut down facebook and other internet data flow centers - harder to do in the USA, but when it gets so bad that the Capital was attacked and people killed it attracts a need to limit incitement.
It used to be a masked man could not enter a bank - in Covid times it happens a lot.
I expect there was a paralyzed board at Parler and when Matze could not make changes that the web hoster or other internet access controlling group, like AWS would accept and no acceptable other could not be found on terms that AWS would accept, and that Parler could also accept = he was toast.
We may be involved in a sea change. The events that led to the riot and the riot itself were turning points.