If the media were there to cover the funeral, then it is a media event. Not sure WHY they would be there. Were they there to cover the funeral or the WBC assholes?
Either way, I think it is obscene as well, but I do have to agree that they have the right to speak their minds about it. I'm not so sure about the lawsuit part, as that would be, AFAIK, a civil action and probably not a constitutional issue.