Obviously subjective and would be determined in a court of law (public figure vs not a public figure). And besides, there are still limits to that regardless. If you publish a damaging lie about a public figure, they can sue you for very large amounts of money as they see fit. For example, if you're the NY Times and you print that a very famous actor is a pedo, and do so without enormous amounts of proof, prepare for an epic lawsuit that you will lose badly.