You have two problems - powdered-butt syndrome and liberal utopianism. Your dad is never going to think you have anything to teach him - he powdered your butt when you were a baby. Liberals believe utopia can be achieved "if only everyone would think like us." They ignore human nature and much of reality.

All you can do is throw facts in their faces - cars kill more people than guns. Crazy could have killed just as many people by driving his car through the crowds before the movie opened.

Keep a smile on your face. If they get you angry, they win.