Is this a serious question? Yes they absolutely are. It's the kkk. They aren't selling girl scout cookies, they're preaching hatred.
And here's where we come to the heart of the issue...
What do you do, legally, to stop them?
They have the same First Amendment rights you do, remember? You may not like it, but unless you're ready to make some major changes to the Constitution, you can't change it. And lemme tell ya, you don't really want those kinds of changes made.
This is why your argument fails, because you're not recognizing that there's a significant difference between what's unpleasant and what's unlawful.