Isn't Morality Simply Personal Preference?

This is the basic argument that morality is simply what one prefers, not a universal ideal. If, however, all morality is simply individualistic, then it would be difficult to communicate across cultures moral decisions or reasoning. It would be just as difficult to communicate in another language.

However, morality across cultural lines is surprisingly easy. For instance, let’s take a movie. There is the movie Avatar which is a very moralistic film—yet it has communicated clearly its moral reasoning to all kinds of cultures, not simply western ones. As well, very moralistic films such as those made by Japanese directors Maiyazaki and Kurosawa are very moralistic from a Japanese perspective, yet they are easily understood by people from all kinds of cultures around the world, after they are translated.

If morality was individualistic, or culturally based, then such cross-cultural communication about morals would be very difficult. However, even if we disagree on a moral reasoning, we typically understand the argument the other person is making. And the disagreements tend to be in application, not in the basic principles of moral reasoning. No one, in any culture, says that it is reasonable to kill an innocent human being without cause. One may argue about the causes that are justified, or one might argue what a human being is, but the basic principle remains the same throughout all cultures. This is amazing and not easily explained. Some level of moral reasoning must be innate. So the question remains, why?