I see your point.
Although, I will say, I would HARDLY call what the Phelps's are doing to be anything close to "polite." They may act calmly once in a while, though, I have seen plenty of videos where they are less than calm. They shout down people, use megaphones, and their behavior is just plain RUDE. You should see the bitch Phelps woman being interviewed by Hannity or someone like that on Fox News a while back before the trial. She would not shut her stupid little trap to allow Hannity or anyone else to speak. Even though Fox News itself uses the same dirty, low-down tactics on a regular basis as well.
But yeah, even if they were "peaceful" and calm all of the time, their signs and message is rude, and obnoxious. I hardly call that "polite behavior." Especially showing up at funerals with such garbage!
I will also make something clear: I don't think that attacking them is the right way to go at all. But I do think maybe there needs to be some sort of stricter limitations of public speech during a funeral, along the funeral route. It is a rather private affair, though they use public streets. It also happens to be an extremely emotional time. Which can very easily constitute as harassment, and emotional distress.