Black Magic

Few days back,I was watching an episode about black magic on National Geographic Channel.Do spirits actually exist?.What i saw in that episode was terrifying.It seems ,in order to cast a spell ,all you had to do was get the photo or hair and that person's life would be doomed forever.The priest destroyed all the belongings of the person doing black magic.What followed was even more horrifying,some fell sick during the ritual of destruction and some even died.Why are people so superstitious?(sic)