The parent would not be directly responsible for his death and in this way he could live life feeling less guilty. In Jocasta's case, when she abandons her son, he feels guilty, consequently after she becomes wary of the prophecies, her guilt grows. In the time period in which King Oedipus is set, people strongly believe in gods, fate, and prophecies, so it was imperative not to anger the god or do anything that would dishonor you or your family and not be admitted to heaven. It is important to recognize that although Jocasta distrusts the prophecy, it is not entirely sacrilegious, and even throughout the story we read of her praying to Apollo. While praying Apollo makes offerings and asks for protection. No one but the Chorus gets as far as Jocasta got with prayer. In many ways you could characterize her as one of the most God-fearing characters in the play. Not that her blind devotion brings her any long-term benefit. It's not really the god that Jocasta is tired of, it's that they are supposed servants like oracles. Throw away the comedy you find