Why we should care about global inequality.

There are obvious reasons why we should care about global inequality, such as lower wages in foreign countries keep costs of products cheap for us living in the higher income countries. There is, however, more important reasons to care. For the simple sake of humanity for one. People are living in less than ideal conditions, working all hours of the day, for next-to-nothing wages all so Billy can get his Nikes on sale.
I guess the ultimate question is: can there actually be global equality? Can the poor countries of Africa and Asia ever be an equal to the United States or Canada or Australia. I don't think it can. The pure definition of capitalism is "an economic system that includes private ownership of the means of production, creation of goods or services for profit or income, the accumulation of capital, competitive markets, voluntary exchange, and wage labor." Just like the upper classes of any country needs the middle to working class for wage labor the higher income countries need the lower income countries to thrive.