Simply put, morality is a ghost that doesn't like to be scienced, and science has been trying its best to make morality go away.
The basic point from the scientific viewpoint on morality is that it does not do anything. Morality by its definition resists scientific explanation. If there's an explanation to why we do things morally, it becomes imaginable that we do something else morally, or not, and either way, "morality" can be seen as a ghost that doesn't do anything.
Think of the marital morality of the praying mantis. Is it moral, or not, for the female mantis to eat the male mantis after marriage? It is in their nature, with a deep reason. Praying mantis evolved to have this kind of strange and cruel (viewed by a human) morality. If they evolved in some other way, they would have a different morality.