Herding is a natural human trait as men with similar DNA, when organized, will generally prevail over unorganized groups of men in times of crisis. This effectively acts to propagate the herding instinct. The value of the herding trait is lower in polite civil society, as there is less violence, and non-herding DNA is less-likely to be culled out of the pool by violence.
So my theory is that people whose minds evolved in violent cultures are naturally more likely to be attracted to ethnic gangs. This might explain why Mr. Uriel Oliva was flashing gang symbols while sitting on Santa’s lap. I also believe that graffiti is closely associated with this type of mind as a mechanism to mark territory.
Per this government gang document, 48% of gangs are black, and 43% of gangs are Hispanic. It is noted that Jamaicans side with African-Americans. The document mentioned Asian and white gangs, but did not indicate how the 9% remainder was split between the two groups.
It is also noted that the herding trait seems to be re-adopted in times of crisis. All white prisoners in the California prison featured on MSNBC were members of ethnocentric gangs and were officially segregated by race.
p.s. I’d add that Jews seem to me to be the ethnicity with the least amount of herding instinct. While they were able to act in unison after 1948 against the Arabs, and kicked butt, Israel’s attitudes towards Arabs and Persians seem largely suicidal today, to me at least. Also see the stuff Hollywood is putting out, and Columbia Law School with its ACLU achievements.
For such a gifted ethnic group, that has self-identified as a population for so many thousands of years, to make up less than one half of one percent of the world’s population, suggests that there is value in the herding instinct.