During the medieval European persecution of witches, there were a lot of arguments about this topic: what is a witch, and what should the church or state do about them? Of course, there were plenty of writers that found Biblical justification from Exodus 22:18, and other passages. There was also an opposing side. One of the most important works from that time is the Discoverie of Witchcraft by Reginald Scot (1584), which comes out very strongly against witch trials.
His main argument is that witchcraft does not exist, but he also says that even if witches could do all the things that witchfinders claimed, that does not mean that they deserve death. He goes at some length through the claimed abilities and practices of witches; it's difficult to summarize, but some of the examples are:
Controlling the weather: Scot says that only God can do this, citing a great many passages from Scripture (such as Psalm 148:8, "lightning and hail, snow and clouds, stormy winds that do his bidding", and Job 37:12, "[the clouds] are turned around by [God's] counsels, that they may do whatever he commands").
Killing people: He says that if they do, then they can answer to the civil authority, just like anybody else who kills somebody.
Curing disease: Again, only God can do this; Scot cites John 10:21, "Can a demon open the eyes of the blind?". He also says that if witches cure with herbs or other plants, they are only using the natural resources that God has given humanity, and should not be condemned.
Renouncing Christ: Scot believes that they would be wrong to do so, but that impiety does not mean they should be executed. He also mentions that "Peter the apostle renounced, curssed, and forsware his maister and Peters apostacie our Saviour Jesus Christ" (for which see Matthew 26:71-75, Mark 14:69-72, Luke 22:58-62, John 18:15-18). In general, someone who sins should be allowed to repent.
Scot also opposes torture, saying "I doubt not but that the pope ... with lesse compulsion would have renounced the trinitie, and have worshipped the divell upon his knees." This is part of his argument that Biblically-derived principles of justice demand that suspected witches should have a fair trial. This would argue against the kind of harassment that you saw, motivated by simple superstition and ignorance.