Ethics is a discussion of how people behave

when a psychologist describes a developing culture as “primitive,” what bias are they displaying

Ethics is a discussion of how people  should behave

The code of ethics that applied in one society may be differ from one geographical location to another.

For example, it is ethical in Japanese society to bow whenever they meet someone new. It's simply how people should behave in Japan. Meanwhile, this code of ethics may not be applied to western countries.