I'm all about freedom of speech and assembly but I feel that this type of behavior should be treated similarly to someone who shouts "fire" as a joke. There should be limits.
Besides isn't it also illegal to incite? If this behavior doesn't do that nothing will.
There is nothing wrong with shouting fire as a joke, unless you're doing it in a crowded theatre and people are likely to (a) believe you, (b) react with panic, and (c) be injured as a result. Although these idiots might induce others to start a physical altercation, it's not a foregone conclusion that every such protest would result in actual injury to anyone. In fact, most people would react to the protest in the correct manner: by ignoring it. The fact that someone with a short fuse might be among the mourners is not taken into account. It is not illegal to "incite" anyone with words. You can't force someone to get pissed at you and beat you up. There's no, "But he started it by saying mean things" defense to assault. Yes, sticks and stones may break bones, but names don't really hurt you.
There is no "sacred" public place that should be protected. There is no "inappropriate" public place for free speech. To say otherwise would be to say people cannot protest in front of the Supreme Court because it might interefere with the court's ability to run efficiently, or outside a church because some clergy member might get "offended". These are the very places where protest is the most effective, where it attracts the most attention and results in the most emotional response.
When we speak of protecting free speech, we are not talking about the quiet, peaceful protest on the village green by a group that generally everyone feels is benign. No one complains about that kind of protest, and no one's going to challenge it. We are talking about protecting that very speech which is noisy, inconvenient, and almost universally abhorred. We are talking about the KKK protesting in the center of one of the most liberal college towns in America. We are talking about eco-terrorists chaining themselves to trees. We are talking about people who take a flag, which many in this country feel is a physical representation of their freedoms, and put it to a match.
These, too, are the citizens of our county. They too have a voice.