Why should Americans and Europeans care about Africa?
Well, China has been investing heavily in Africa because Africa is a contintent which a large amount of untapped unnatural resources. It's also a continent that is ripe for manufacturing, urban development, etc, agricultural development, etc. And don't forget the number of Africans who will become consumers of Chinese goods and the countries there that will have China's back.
If its too much to ask Americans to take and interest in the "dark continent" out of sense of altruism, then perhaps we should think think about it out of a sense of self-preservation. In order for any economy to grow, you must cultivate new markets, and unfortunately, there aren't that many more places on planet where we can sell our junk. No company is really going to want to invest in a country that's completely unstable and ruled by a crazy dictator who sees nothing wrong with murdering a large percentage of the working class. Which is why the U.S. should get involved; to make the world safe for demo-uh-capitalism.
And at least under capitalism vs. a colonial economy, the workers have to make some sort of money so they consume more goods.