Here is my view of this issue:
- There are African traditional religions which include magical practitioners. In the 18th and 19th centuries, these practitioners were mislabelled as "witches" by Christian missionaries and colonialists. At that time the word "witch" still had almost entirely negative connotations. When these people's roles are being translated into English by Africans, they don't use the term "witch".
- African traditional religions have two categories of "witchcraft":
- involuntary "witchcraft" which is a disease that the "witch" often doesn't know that they have. This is a complete misuse of the word "witch". (See Witchcraft among the Azande by W Evans-Pritchard for an anthropological study of this type of witchcraft belief.)
- sorcery or malevolent "witchcraft" - again, this has its own set of African words which probably don't map precisely onto the European concepts.
- During the late 19th and early 20th century, various European writers began to see witches as just traditional healers who were misunderstood, and so the word "witch" came to have positive connotations in some quarters; Gerald Gardner picked up on these writings and created Wicca (or the people who initiated him did so).
- This new positive understanding still hasn't reached many evangelical or fundamentalist Christians, who regard all magic as being of the devil. The more enlightened Christians understand the difference between contemporary Pagan Witchcraft, the negative stereotypes of the 19th century, and the magical practices of African traditional religions.
- In some circumstances, it may help to label traditional healers & magicians as being like Wiccans (where Wiccans are held in positive regard); in other cases, it may not (where Wicca is regarded as just another decadent Western practice, for instance).
- Labelling all magical practitioners as "witches" is a bit too much like saying that anyone who does anything that looks like shamanism is a shaman, when they may have their own indigenous term and understanding of the practice which is different from that of the original shamans of the Tungus in Siberia. People's practices should be understood on their own terms, and not in terms imported from another context. It is quite correct to say that understanding it in terms of "black magic" versus "white magic" is very unhelpful. I'm just going one step further and saying we should be extremely careful in applying European terms, metaphors, or concepts to the situation; if we do so, we need to understand it in terms of the historical factors which might be causing the situation, and to be aware of the differences as much as the similarities.