Let’s say a man decides to change his last name for no other reason than he hates his dad’s last name, and that dad refuses to call his son by his new last name. Then, in my opinion, his son should be 100% allowed to call him any mean name or slur he wants—'dick,' 'shithead,' the R slur, whatever. You shouldn’t get to disrespect people and expect respect back, so if this person gets called a slut and gets mad, I really can’t feel sympathy for him.