Perfectly within her rights to do it
It's a petty reason but they are perfectly entitled to say whatever they like
CheckD3 said:
That's one of the problems introduced with freedom of speech and there needs to be no limit, otherwise it's not freedom of speech
However the KKK style is not freedom of speech, that's vandalism and probably some hate crimes involved too. What they say can't be prosecuted but what they do, that's much easier...
Also it doesn't stop the public from retaliating against them