They believe that doing evil and harm is against all ethical and moral laws. Witchcraft is a religion that underscores polarity and views the God and the Goddess as equal entities. A Male Witch is simply that.
Many Witches do choose to wear black clothing or ritual robes.
The color black is the culmination of all vibrational rates of light on the material plane. Black absorbs light information and helps Witches be more receptive to psychic impressions and energies. Many Witches are professional people holding positions of responsibility such as Doctors, Nurses, Police Officers, Teachers etc. Witchcraft does not discriminate against color or ethnic origin and does view everything as equal in the eyes of the Goddess and the God. A spell is a thought, a projection, or a prayer.