I think a lot of people are sort of obfuscating the issue here--which is that "Witch" and "Witchcraft" can mean different things depending on the context.
Modern witches, or Wiccans believe in two deities, a god and a goddess, and believe in casting spells by invoking their powers, often by personifying them in classical pagan deities of myth. Obviously as Christians we don't believe these things, but Wiccans have the right to practice whatever they want as long as they don't hurt anyone. And not hurting anyone is a fundamental rule of their religion.
Witch and Witchcraft in the Harry Potter sense of the word is completely fictional. It doesn't exist, and is used as a mechanical device for the storytelling. This should be obvious to anyone who has actually read the novels or watched the movies. If you try and alter reality by pointing a stick and chanting a quasi-latin phrase, reality is going to laugh in your face and go "What'chu talkin'bout, foo?"
The term 'witch' as used in Exodus is translated from a Hebrew word that refered to people--usually women but sometimes men--who casted evil spells to harm others. The ancient Hebrews didn't have a conception of the occult as we do today--secret magic practicioners teaching each other a unified art. The 'occult' was clearly visible in every aspect of anciet life, and some of the methods of communicating with God used by the ancient Hebrews would probably seem occultic to us today.
The passage is Deuteronomy lists several forbidden divination techniques as well--though there are other divination techniques mentioned in the Bible that aren't forbidden; make of that what you will--and also forbids snake charming. It's my personal belief that these techniques were forbidden not because they're 'evil' but because they don't work. Only God can truly know the future, and trying to predict it with magic is dumb. As for charming snakes, it's dangerous because snakes tend to, well, bite.
So, in conclusion, Harry Potter is just a fantasy and people who think it teaches real evil need to do their research.