For philosophers, ethics originates from divine revelation — unless it is based instead upon intuitions or self-interest or utility or consequences or social contracts or civic duty or emotions or sentiments or desires or reason or virtue or natural rights or power or ... something else.
For anthropologists, ethics is cultural.
"Culture" is the prime explanatory matrix for anthropological science, a paradigm that unifies the scientific discipline of understanding homo sapiens through the lens of group behavior. The science posits that the human species is not only social (so are ants and dogs) but more importantly, cultural to the core. Even when we look at just one human being, we are seeing a member of a culture.
This assumption — that "homo sapiens is a cultural animal" — proved its explanatory usefulness in the 19th century and has deepened ever since, informing countless scientific studies of human communities, past and present. In the 21st century, culture is viewed as more than something special that humans do, and more than just the de facto context of human life. Culture is, in fact, the key to human nature — nothing less than the adaptive evolutionary strategy of our species.
Culture is the first assumption in the anthropologist's view of moral behavior too. Ethics is treated as just one part of a broader cultural pattern. Morality is viewed as woven into culture.
As an empirical philosopher, I accept that paradigm. Academic philosophers should abandon the sterile analytical argumentation of the past and consider culture as the proper root of meta-ethics.
To understand ethics, understand culture.