As gcol said, free speech was never meant to protect the majority. Instead, it was meant to (like most clauses in the first amendment) protect the often unpopular minority. While there are days I'd like to stick Michael Moore into a meat grinder or take a cheese grater to Al Franken's smug face, I respect their right to speak. And they're arguably a bigger threat to society than any kkk member or neo-nazi member.
Because, really, the only KKK member with any influence on society is Democratic Senator Robert Byrd.
"Compromise, hell! That's what has happened to us all down the line -- and that's the very cause of our woes. If freedom is right and tyranny is wrong, why should those who believe in freedom treat it as if it were a roll of bologna to be bartered a slice at a time?"
RIP Jesse Helms