[ZenoArrow]

If you're getting hung up on the word vigilante (which has been the case for most people who replied to my earlier comment it seems), replace the word 'vigilante' with the word 'street', i.e. street justice. Note my intended meaning hasn't changed, only the way I'm choosing to express it.

Now what prevents street justice in a society without government intervention? The (simplified) answer is self-organised defence organisations. Is a mob/gang boss a preferable means of protection in a community, compared to those means that can be put in place by an elected government?