It is objectively true that Norway, compared to the US, is a racial monoculture. Sociological evidence suggests ethnic diversity correlates negatively with social cohesion, though recent studies also suggests that while causal, the effect depends significantly on their prior preferences.

That's not saying "people can not trust others of a different skin color", but it is saying that generally speaking, people in more ethnically diverse communities are less trusting of each other. Call that what you will :)

It isn't just about skin color, it is about in-group favoritism. Most people tend to seek out similarities to others in groups depending on the context. Could be sex, race, profession, hobbies, interests, etc. There definitely is a scale of how people treat those they have categorized as out-group as well.