You can make a better case that Liberia is America's fault than you can for any other country in Africa. Liberia was established by American nonprofits as a way of "resettling" freed slaves. It became an effective colony of the United States.
And what's to stop the descendants of freed slaves who are protesting in Ferguson against the right to be governed from doing something useful like organizing and going to Liberia to provide their brothers and sisters with help in battling disease?
The message I'm getting, that I'm probably not allowed to say in this PC world, is that the vast majority of Africans can't self-govern. And they should stay where they are until they figure it out.