In no event, however, shall any owner, licensee or operator, or the agents or employees of any such owner, licensee or operator of such a television and/or radio station or network of stations be held liable for any damages for any defamatory statement uttered over the facilities of such station or network by any candidate for public office, where such statement is not subject to censorship or control by reason of any federal statute or any ruling or order of the Federal Communications Commission made pursuant thereto; PROVIDED, HOWEVER, that this section shall not apply to any owner, licensee, or operator, or any agent or employee of such owner, licensee or operator, of such visual or sound radio broadcasting station, or network of stations, when such owner, licensee, or operator, or agent or employee of such owner, licensee or operator, is a candidate for public office or speaking on behalf of a candidate for public office.