I think you need to go back and research the gang activity in LA, Chicago and NYC. In the case of Chicago, its about as bad as it gets. I personally work as a firefighter in California and deal directly with Mexican gangs that are supported by the Mexican mafia - drug trafficking. This is no Shangi La here.
Also, the diverse population here is stratified by wealth. ie...minorities are mostly poor. The richest Hollywood executives are all from the same ethnic group - and almost exclusively male. The other big industry in California is military weapons production. I wouldn't exactly characterize this situation as "xenophilic".
You also might want to do some research
murders per 100,000 people in 2014
California
4.4
New York
3.1
and lets compare it to some states that are not known for there gang activity
Alabama
5.7
Alaska
5.6
Georgia
5.7
Louisiana
10.3
Mississippi
8.6
NATIONAL RATE
4.5
Seems to me California, a state renown for its gang activity is slightly bellow the national average for murders per capita.
In case you want a source, it comes right from the fbi
https://www.fbi.gov/about-us/cjis/ucr/crime-in-the-u.s/2014/crime-in-the-u.s.-2014/tables/table-4
Also the problems in L.A. are rooted in racism and lack of tolerance, the same that goes for most cities. After world war 2, you had the gi bill, which aloud returning American veterans to get almost interest free loans for just about what ever they wanted. New house, new car, education, starting up a business, so on so forth, as well as many other services. The thing is, black people were not aloud to partake, and have bin at a major economical disadvantage since the freeing of slavery because of segregation.
The gi bill aloud non black people to move out of poorer location, and into new suburbs popping up every one thanks to housing bills for the veterans, while black people were more or less forced into poor run down locations. Once the black people were in the poor run down areas, the cities purposely under funded civil services for the forming black ghettos.
In closing, the gang problems in major cities are the direct results of racist polices by the "greatest" generation.