I think that it would fall more to the category of religion only because most of what Voodoo is based on is mystical and magical. They have their deities that they worship both good and bad. but, they are called upon generally for protection, assistance, revenge, remorse,guidance, or even help. Whether they are making a mojo potion for love or if they are putting curses on people, places, or things. It is all for some type of personal gain.
Although they maybe conjuring spirits or demons for these purposes it is still in a religious type ceremony. Just as a Christian will pray They would Conjure.
I can see were there could be a similarity to the Paranormal field on because we are both seeking contact from beyond the grave. We just don't do it to hurt, harm, or even, help our selves or others. We are searching for truths in the Paranormal field were as they are following a Spiritual Belief.
Now this is just my personal belief I am really anxious to hear what everyone thinks on this Subject. So don't hesitate to post your opinion!!!