If a girl is into witchcraft and hypnotizing people, why is it wrong to call her a witch?

Well sounds a bit odd that she does that.Also, it doesn't mean she is a witch; It just means she does spells and tries to hypnotise people. There isn't anything "wrong" with calling her it as in being mean but it may not be true so you shouldn't just go round labelling people. Lots of people seem to think being a witch is such a bad thing , so they would think it's being nasty about someone, and she may feel the same unless she actually identifies herself as a witch.