Let's say it wasn't witchcraft thing but something more widely accepted like prayer session at mainstream church/mosque or something of this sort. Wouldn't the devout people see this as a contract killing? What if the soother says he felt possessed? Shouldn't then he be let go in a religious society?
And with our Supreme Court, who knows if they'll say witches casting spells are assassins after all.
Many of the witches who believe in this stuff also believe that what you put out into the world will come back to you, typically with a multiplier.
Presumably, some of the Christians who believe in this stuff also believe "Judge not, that ye be not judged" and that ultimately God alone must and will mete out punishment with the wisdom of divine omniscience.
None of this stopped people who claim to be witches from taking money to curse a guy, and in my experience, people who claim to be Christians love judging others and their zeal for punishment often seems fetishistic