‘Voodoo’ has come to represent something evil when it appears in popular culture. ‘Black magic’, witchcraft – it’s always portrayed as something to be feared. But in reality, Vodou, as it’s correctly written, is an official religion practised by millions of people. Why has it been vilified for so long? Josh Toussaint-Strauss looks back over the history of Haitan Vodou and Louisiana Voodoo, which is a separate belief system altogether, and its portrayal to find an answer