Without the mountains there can be no valleys, without darkness there is no perception of light. We can only measure good by the amount of evil there is and hatred is only another form of love. The law of duality is a part of creation, and that is why we have God and Satan. God is extreme Light and Voodoo is the same light in a much darker form.
The laws of action and reaction are also real. So when we use the darker aspect of light (occultic black magic), we are also inviting the negative aspects of karma. Voodoo is real and is the darker aspects of consciousness, used in a negative way. It has its repercussions. Beware!!