Folks with very different ideas of personal space, ownership, community, responsibility will naturally have larger friction between members.

The US has selective enforcement of laws...minorities are far more likely to be arrested for things like drug use than those in the majority. The US has a social safety net for the poor that's pathetic compared to most EU countries. And the US has employment practices that make it difficult for most people with a criminal record to ever get decent employment again.

Poor, desperate people who feel like their future options are limited are far more likely to commit crimes than those who are financially comfortable and/or believe they have promising futures. Diversity doesn't necessitate higher crime rates, but our diversity combined with our policies does.

And Norway is #146

I'm not arguing for or against, but the list seems to use language as a basis for cultural diversity. While language might have a correlation with cultural diversity, it doesn't seem fair to use that as an argument for what countries are more culturally diverse. Also, how countries report their numbers greatly impact these sorts of assessments. Lastly, comparing more tribal-based countries with modern countries also makes it tricky.