If we step into the story and see a misguided character doing hurtful things to others and even to ourselves, from OUR life experience we determine that character must be stopped. Perhaps we argue with them, try to educate them, fight with or kill them or just write them off, severing our emotional ties and letting them spiral down into self destruction because it is the only way to avoid being dragged down with them.
Or, we might argue with them and find ourselves convinced of their point of view, try to educate them but learn something instead, fight with them and lose or be killed, or be written off BY them or hold on to them and be dragged down as well, or drag them down with us.
The point is, both Main and Obstacle characters will feel they are right, believe in what they do, try to convince or thwart their counterpart and ultimately prove to be correct or misguided.
From the Dramatica Theory Book