How does labeling other groups as heathen or savage demonstrate cultural absolutism

It is place the two cultures on two ends of a scale: By calling one savage or heathen suggests they are the lowest form of humanity and even lacking basic human functions.

This type of cultural thinking doesn't allow for thought of culture in the middle. It sees cultures as either good or bad; civil or uncivil; heathen or saint, etc. It suggests there is no in between in the cultural assessment.