If those eighteen Klansmen had been, instead, Communists carrying red flags, everyone in the crowd would have agreed with the woman. They would have protested the lack of loudspeakers. Liberal freedom of speech means freedom of speech for leftists only. A union based on nothing but words cannot tolerate any serious diversity of opinion. A union, by definition, must be united by something.
All principles are opinions.
You can only be a citizen of such a country if you have the right opinions. Eventually, that means that if you don't think right, you are a traitor. A natural nation, based on a common heritage, is going to have principles in common. They will flow from the common heritage and they will dominate naturally. But such a natural set of common ideas can tolerate dissent, even extreme dissent.