To make things clearer, change it from oil to a lake that you own. Access to the privately owned lake is scarce for artificial reasons. Property means control over something, and if you cannot maintain control then in many cases there is no benefit in possession/creation. In this respect property is always the same, whether physical or intellectual: owning the land or copyright only works if you control access/distribution.
Of course with a limited thing like oil there's also the fact that not only would you be unable to capitalise, you would be unable to even be the end-user of the resource, when people steal it. But that's just an extra dimension to consider, not relevant to the core ethical issue, as the grandparent poster was trying to say.
> Access to the privately owned lake is scarce for artificial reasons.
Again, No. Ultimately, access is limited by physical limits: not everyone can easily travel to the lake and not everyone can fit in or around it. These things do not apply to data: everyone can make a copy.
> and if you cannot maintain control then in many cases there is no benefit in possession/creation
And data/information (abstract goods) are exactly a case where this does not apply. Abstract goods are nonrivalrous: your use and benefit from them does not limit mine.
Of course, there are probably various ways to construe 'property' to accommodate abstract goods, and whatever else, and they may even be useful and practical. But with abstract goods there is something different in physical fact. Surely that is the most important thing to have in mind if you want to consider ways of handling it.
As to the ethics, the physical basis is critical, because it is where the buck stops. Since copying renders no direct physical harm to the copyright 'owner' it must make us think differently about it.
The physical limit is still irrelevant to the debate: the number of people who want to use the lake could easily be far less than the number of people who potentially could use the lake. In this situation, the lake is artificially scarce according to the owner's property rights, not because of any physical limitations.
The physical basis is just an incidental detail. The ethical basis is that individuals must use their minds to survive, meaning they must have ownership over the produce of their minds to survive, meaning they must have property rights. To say that somebody who creates a work, whether intellectual or otherwise, should not have control over its access/distribution, is to argue against property rights and indeed the right to survive.
As the previous poster argued, pirating/stealing my intellectual property amounts to removing my ability to profit from my creation/property, which amounts to direct (physical) harm to me, the copyright owner. True, it doesn't stop me using my creation, but that's hardly the point. What if I invent a perpetual motion machine, should just anyone be able to then tap into my non-scarce energy source without permission? Besides, saying property should be granted on the basis of physical scarcity says nothing about why it should be granted to a particular person - it's a poor criterion all round.
Of course with a limited thing like oil there's also the fact that not only would you be unable to capitalise, you would be unable to even be the end-user of the resource, when people steal it. But that's just an extra dimension to consider, not relevant to the core ethical issue, as the grandparent poster was trying to say.