I think mobbing is an instinctual way of trying to get rid of something that disturbs a group -- instincts do not take thinking into account, and so are likely to rule in early societies, before the discipline of trying to solve problems by thinking about them gets established. Instincts have been established through evolution, and so are very powerful. Thinking about frightening emotions is difficult -- frightening! As humans we always seem to have the conflict between instincts and thought. Thought takes time, while instinct can be instantaneous.