In a specific case, perhaps. But surely, I can't go out, make a broad statement like, "XYZ is a liar and fornicator" and leave it there. And how would XYZ go around proving they are not a liar and fornicator? Talk to everyone in the world and get them to confirm they were not lied to or sexually involved?

Surely, at some level, you can be sued for making unfounded remarks. But then IANAL so, meh.