So his opponent is practicing her Freedom of Religion. In this instance, Wicca. If he's a solid Catholic, he's free to go drink the literal blood and eat the literal flesh of Jesus (after transubstantiation) during mass. By the same token, she should be free to perform whatever spell/s she likes. That doesn't make her 'demonic'. Unless she's literally summoning demons, in which case, Masterson needs to play The Best Song in the World.