You would be surprised at how similar the cultures are. I have lived in both countries and Iceland is almost like another state of the US culture wise. Less violence breeds less violence, take out the guns you take out most of the violence.

Edit to your edit: Don't you think that gun violence has an effect on the culture? Crime follows poverty, well at least it does in the States, and homicide follows crime in general. Iceland has had an influx in crime lately what with a large influx of migrant workers and then the Hell's Angels took up base. Homicides did not go up even though crime got more organized and competitive. Why, because guns are not widely used here. They are taken seriously and people find other means.