Ancaps should understand that Private Property, like Government, is an institution that requires the threat of violence to enforce. It’s only “defensive force” if you agree to an unlimited right to property, which is the monopoly right to exclude others from using a resource. Step back and think about it.
Some people don’t believe in ownership of ideas (patents)
Some people don’t believe in ownership of authored data (copyright)
Some people don’t believe in ownership of large swaths of land or lakes, resources, including houses etc.
Most people believe in enforcing chattel property.
But as you get further from that, you need an organization and laws to enforce it. At some point the right to property must be balanced against other rights, eg the right of a squatter to have shelter from the elements vs the right of a landlord to enforce rent over 50,000 properties.
There are various positions. Generally most disagree with the concept of intellectual property as it is now.
There are some who would disagree that property as in land can be owned outside of the ability to utilize it. Many point to the first principle of ownership stemming from utilization and improvements upon the land.
Generalizing about ancaps is a difficult proposition. "Herding cats", is an apt description. However your final statement seemed divorced from anything advocated by anarcho-capitalists.
There are real pragmatic concerns about advancing anything outside of the current paradigm. Even within the narrow confines of what is possible with the current system, we see deadlock and endless bickering.
At the end of the day reading political philosophies can be interesting, but not fruitful in the real sense of bringing about change. Just the same, misconstruing the arguments advanced within these philosophies isn't helpful.
Some people don’t believe in ownership of ideas (patents)
Some people don’t believe in ownership of authored data (copyright)
Some people don’t believe in ownership of large swaths of land or lakes, resources, including houses etc.
Most people believe in enforcing chattel property.
But as you get further from that, you need an organization and laws to enforce it. At some point the right to property must be balanced against other rights, eg the right of a squatter to have shelter from the elements vs the right of a landlord to enforce rent over 50,000 properties.