The riots in South Tel Aviv are further evidence of the violent racism among Israel's Sephardi underclass. It's part of a worldwide, historic phenomenon among poor people that the left doesn't want to face up to.   As a matter of principle, I think Israel has to relocate the great majority of African refugees from South Tel Aviv's poor Jewish neighborhoods. It isn't fair to the Hatikva and Shapira quarters to have to absorb such a large, alien, troubled and in some ways troubling population when middle-class and upper-class Israel don't have to absorb any refugees at all.  I believe that if left to its own devices, society will turn…