While tempting as an explanation, it is actually more complex than that. Norway today e.g. is quite diverse. There are more people born abroad in Norway today than in the US (in percentage terms). Yet the trust between people is at an all time high. The political conflict is at a historical low.

Norway in the 1930s for instance when there was next to no immigrants was extremely conflict ridden. Norway has had deep conflicts over language, class, workers vs farmers, workers vs burgoise, cities vs rural areas.

I think in the US there might be a sense of "the grass is always greener on the other side." I think many in the US have a bit of a romantic view of the Nordics as a place where everybody has always just gotten along very well. That is a bit of an illusion.

In Finland they got along so badly they had a civil war in 1918. And keep in mind that the American South and North remained in one union while Norway and Sweden splintered into separate countries in 1905. Norway and Sweden while in a union was on the brink of civil war on several occassions.

Norwegians are not really one homogenous group that just get along by default. People have lived very different lives around in Norway for over a thousand years, developing unique regional characters. In the 1960s newspaper ads in Oslo for housing would explicitly state that Northern Norwegians were not welcome.

I grew up in the 1980s and remember even then Northern Norwegians faced a lot of prejudice. I remember a buddy of mine who was a bit of an asshole. A kid from Northern Norway had started at school and my buddy went up to him and asked: "What is it like being around intelligent people for a change?"

A kid doesn't just say that kind of stuff unless those ideas get picked up somewhere. For the Sami people it was much worse. I remember when I grew up, all the stories we told each other about Samis. Not very positive. There would always be some infamous Sami people knew about in the neighbourhood. In my hometown the rumor was that they used a Sami as a guard at a warehouse or store because he was so crazy and dangerous. I suspect a lot of it was nonsense or exaggurations.

The point is that a lot of the homogenity and tranquility in Nordic countries today is somewhat of a manufactured reality. We built this kind of society deliberately. It very much began with the social democrats who sought to end class divisions and which they very much pull off.

It was never as bad in Nordics as in Britain, but we also worked much more towards reducing class divisions than Britain did. The British Labour never had much power in Britain while in Scandianvia you had Social Democrats in power for something like 70 years.