Agreed, but the US Civil war wasn't started over mean tweets or nasty letters. There were armies and battlefields. The Declaration of Causes of Seceding States wasn't threatening individual lives, but simply said that some states need not respect the federal union.
Also, that threat of violence didn't lead to the success of the Confederacy, but to its destruction.
I mean there was the whole civil war thing…
If a movement has millions of people, possibility of violence is implied if you piss then off enough.