The ACLU defends everyone's right to gather in public protest, even if the speech is frowned upon by many. That's the beauty of the First Amendment--we all have a voice.
You've no doubt heard of Fred Phelps and the Westboro Baptist Church. The group's messages are highly controversial and upsetting to many. But direct from Comic-Con in San Diego, a great example of why the best antidote to bad speech is more speech: http://tinyurl.com/27kx2e5