Is killing a witch always a bad thing?

[Esquilax]

Google it, Witchcraft is a real religion, albeit very benign today. A few hundred years ago it was the only real option to Christianity in the west. It's practitioners did all sorts of terrible things in the name of satan. Whether satan endowed those people with powers or not the underlying fact is that much torment and destruction was doled out in his name. Much like the crusades or inquisitions.

That in mind the question stands how much would it take to kill someone else who was trying to worship their deity by tormenting you/your family?

I get that witchcraft is a real religion, in the same sense that christianity is; they both have untenable beliefs that don't match with reality. I was asking whether you were posing your hypothetical as a literal magical assault, or a physical one done under the auspices of a religious witchcraft ritual.

The former obviously isn't going to happen, and as for the latter, that's what laws are for. We've had self defense clauses in our laws for ages; why would a witchcraft based assault be any different from a regular one?

Pointy hat aside, that is.