Let me reiterate the general point that illustrates perfectly, albeit horribly, the arbitrary of stigma and prejudice, and the corresponding violence exercised against a stigmatized category. Any physical marker can be latched upon and used to mistreat an entire category of people, something that essentialist approaches to race and ethnicity completely miss.
Any physical difference from the norm can be seized upon and used against the individuals who can do nothing about them. These individuals, deviant because of a physical characteristic (in this case, one they do not control) are then subjected to dehumanization and violence, used as scapegoats and otherwise see their capacity for social participation drastically limited.
In this case, the combination of social stigma with traditional beliefs and possibilities of profits on both side of the transaction (witchdoctors and patients) and the inevitable police corruption create a deadly situation for many albinos in that region.