Africa is a large place and many places aren't as you describe them. Regardless they've had to deal with a legacy of colonialism and asset stripping for a few hundred years. As for Haiti the U.S. has a habit of running coups on when they elect governments that will do something for them. The latest was done by
Hilary Clinton in 09 as Secretary of State to install a neoliberal government to stop reforms that would improve peoples lives.
You live in the core of an empire that's siphoning off the wealth of people across the world by installing governments that answer to Washington and not the people that live there, and then wonder why they live in shit countries. They come to the U.S. where they are often exploited again, because by and large the U.S. has stopped where they come from improving the lives of common people.