That's not to say you can't protect yourself with magic. For instance, if you need someone to leave you alone, to stop calling you or something, you can put their picture in the freezer and this will make them stop trying to contact you. But it doesn't cause any harm to the person. There are people of all professions who are witches. It's just about having an interest in the sun, moon, stars, nature, and wanting magic in your life.
Black magic has malicious intent.
This magic usually works faster than white or green magic, but the consequences are far worse. Witches believe that when you cast a spell, you get back nine times what you send out. It's like karma. Traditionally, most witches were female and the broom is a common tool of domestics. Women would prop a broom outside their door or up a chimney to let people know they were away.