Most of the medical witch were actually interested in curing illnesses and other good stuff, with only a small minority delving into the mad science stuff.
The great sages were probably the stereotypical Lawful Neutral paragons, with an overly strong sense of Order and less empathy for actual people, maybe personally hurt in some way by the evil guys.
The sage guys tried to limit (or ban) body magic, probably with good intentions (at least in their eyes), while the healers opposed the decision, for reasons as good as the sages' ones; a radicalized sect inside the healing field, as well as other witches dissatisfied with the status quo, took the chance to escalate the tension to the point of an all out war.
The survivors of the radical group are now the brimhats.