This belief misses the importance of protection of individual property rights in society from both internal and external threats. The reason for a court system, police force, military and government to oversee it.
This is one difference between Libertarians and Objectivists, the latter advocating the need for a strong government for protection of a free society.
For completeness, Objectivists also advocate laissez-faire capitalism under the rule of law, therein no government intervention in the economic system. The laissez-faire capitalist belief overlaps with Libertarians view that governments shouldn’t intervene.