Consider San Francisco. Environmentally friendly, hugely supportive of diversity in all its forms, achingly concerned about the oppressed of all types, a $9.14 minimum wage, "uninsured residents under age 65 are eligible for universal health care": verily, it seems to be a Liberal's paradise on earth.
But one question: why are so many African-Americans leaving?
Well, because of "High crime rates in some of the city's surviving black neighborhoods", "Substandard public housing", and--oh, this is interesting--"Dissatisfaction with underperforming urban schools".
You can't make this stuff up.