The method of casting shame allows a narcissist to feel superior while minimizing any impact the other person might have. It also serves as a way of discounting any future comments the other person may use to embarrass the narcissist.
Blaming your parents not only keeps the wound alive, it also tells your subconscious mind that your parents currently have power over you or your life, and, therefore, blame programs you for disempowerment.
The most important thing to remember about intentional abuse is that it’s designed to dominate you. Abusers’ goals are to increase their control and authority while creating doubt, shame, and dependency in their victims.