Well, freedom of speech does not mean you wont be in listening range of something you dont want to hear. There is no protection from stupidity or the jails would be as full as a mall during the Holidays.

You cant do Bomb jokes, or report a false report - best to ignore it. I have encountered the religious that will do anything to strike up a conversation. Or just busy bodies that wont take no for an answer. You may just have to walk away. Not right you have to, but there is no protection from hearing someone elses stupid speech (yet).