Gather in the middle of "town square" and start screaming racial slurs and threats of violence at minorities and the cops will remove you for disturbing the peace.
Direct threats to violence though will likely not be protected as it would stifle free speech. But, saying that some speech could "maybe" or "potentially" lead to violence down the line is usually not an argument against allowing it.
Besides, it should ideally be a democratically elected civil government who decides these matters, not for profit private companies and its leaders.