I agree... there are no free-riders with a 100% individual based private property system: you show weakness, you lose the ability to defend your property with force, you will be slaughtered and your property will be taken... gorillas practice this system... zero free-riders. It's not a civil society; it's jungle law.
Discussion
Hell, I just realized even the lioness on the savanahs are more conceptually advanced than the edgelord libertarians... the lioness pay the male lion solely to do nothing but to provide protection over their private property (lion cubs) so another male doesn't come in and kill them
See, this is a conceptual hangup that the criticism doesn't understand. Neighbors will be incentivized to collaborate with one another, it'll be more efficient for a security force to service a neighborhood than individual homes.
Private Court systems will have accountability for unjust practices by having competition.
If someone gets murdered for their property, there is still civil and criminal law. The murderer doesn't just own it by being present on the property. AnCap/Libertarians are not for no government, its for voluntary governance.
People practice a limited form of voluntary governance by moving between countries/states/cities. To think that a purely Private Property oriented society would be Chaos and unforgiving is a naïve strawman.
Private criminal courts. You run into the problem of legitimacy... What gives you the right to judge me? An accused criminal would say. A monarchy government would claim God, a democracy the will of the citizens... a private group of people paid by the accuser has the legitimacy of a hired lynch mob.