Even DJ's can slander ... in fact, because they have (presumably) a larger audience than news programmes, and the listeners are (again presumably) listening less critically, they are in a position to do much greater damage. Also, they have no professional standards to adhere to, such as obtaining independent verification of items they intend to publish.
I think it's a shame the radio station wasn't sued and forced to pay substantial damages, but the sad thing is, the station would probably manage to turn it into a publicity event for itself.
Freedom of the press is vitally important to a free society, but that doesn't mean it should be completely uncontrolled and answerable to no-one. So I think the press should be allowed to do and say exactly what it thinks it must say, but it should have to answer to a responsible supervisory body for any complaints against it, and if it is found to have abused its privileges, to pay a very heavy penalty, including, in the worst cases, closure of the newwspaper/radio station/tv station concerned. Compensation payments would also seem appropriate in many cases too.
As for the tripe that you find in the gutter press, I think they can be safely ignored: they don't matter, and the people they write about don't matter, either. They feed off each other in order to make each other rich at the expense of readers and fans eager for the latest gossip and scandal. It's a source of wonder to me that there is so much money involved in what they do.
TYWD