Thanks!

And I can definitely see the cultural distinction. Although based on what little I know about US street gangs like the Bloods and the Crips there is still a "gang culture" in certain neighborhoods as well. The indoctrination starts young for them as well, with boys taught to be hard, to never shy away from violence, to show solidarity with your set, etc.

Again, I am no sociologist, but I would reckon that wherever you go around the world you're going to find this sort of criminal culture prevalent in communities that have been marginalized by mainstream society. African-Americans and other minority ethnicities in the USA (including Italians in the early 20th century), "untouchables" and Korean-Japanese with the Yakuza in Japan, the rural poor and the cartels in northern Mexico, etc.