Morality is relative. Before lecturing someone on their belief system, reflect on your own ideas. Are they really superior to anyone else's? Do you expect to change a person's outlook by chastising them? Rather than giving a lecture, try to find common ground with this individual. You will be surprised to discover you have many similar interests. Listening to music, exchanging books and enjoying foreign food will be the basis for a firm friendship. At that point, you'll gain an appreciation for their outlook.