Ethnic diversity was never a problem. Money was the primarily problem, especially for the economically disadvantaged blacks and hispanics (and whites) who've been recruited or forced into crime because they had no other way of earning money, other than to clean toilets or pick strawberries. When the lower income people react to this - because of the absence of upward mobility in society - there is racial tension. Yes, people inherently dislike the 'other', but they are prompted to act on their hatred when they are miserable and have no money.

And yet, for some reason they don't place their hatred on their real oppressors.