To many sociologists, the answer is 'racism'. And that's where the indignity comes in.
Most hard scientists take a different view.
What is behind the extraordinary reality that over the past 30 years, as equality of opportunity has steadily increased in sports, spreading to vast sections of Asia and Africa, equality of results on the playing field has actually declined . Greater opportunity has led to greater inequality in performance at the elite level between ethnic groups in a range of sports. Nigeria, Cameroon, Tunisia, and South Africa have emerged as soccer powers. Africans have also become fixtures in Europe's top clubs even with sharp restrictions on signing foreign players. In England, which was slow to allow foreigners and has a black population of less than 2 percent, one in five soccer players in the Premiership is black.