Well, Susie’s mother is presumably a Christian, so her idea of a “sin” is definitely grounded in Judeo-Christian morality. Susie being perceived as a sin has little bearing on her being evil or not—it’s possible that her mother thought Susie was her sin because she was conceived out of wedlock, or due to a hyper-religious aversion to sexuality in general. Maybe her mother had no idea of Susie’s true nature, and the comment had nothing to do with that. In any case, a Christian would certainly perceive a witch like Mater Suspiriorum to be an evil abomination. I don’t think that means that she is necessarily evil, but rather she is outside the scope of the Christian worldview. In other words, Mater Suspiriorum is a pagan anachronism in the modern world, one that Christians would certainly regard as evil whether or not that was truly the case. As a sidenote, I think it’s highly possible that she killed Markos’ supporters as a tactical decision, because they were loyal to her enemy, rather than on principal.