I'm not sure the point of this article is that nothing is being done by the US, France, or whomever else from the outside, it's that there is no outcry about the attrocities.
And the reason is simple. Racism. Liberal white racism. And liberal black embarrasment that their liberal white friends are racists, who honestly believe that civilized behavior must be demanded of whites, but cannot be expected of blacks. Ugandan President Museveni has discussed this phenomenon at length several times, though he's enough of a statesman to avoid the "r" word, as well as the "l" word.