The people who believe property rights are "natural" aren't saying they aren't a human creation at all. Just that they are a human right, like other rights that are also human creations.

The justification for this is something like you own your labor and slavery is wrong, and if you use your labor to produce something, it's unfair for anyone to take it from you. Likewise it's your right to trade it for something someone else made, or do whatever. And from that you get capitalism and property rights as we know them.

However this argument doesn't cover property rights over natural resources or land. There are some arguments for that like the homesteading principle. But in general there is an argument to be made that natural resources should be publicly owned, or at least rented with the profits going to the public.

Also this argument is deontological. A consequentialist would say if violating someone's rights helps more people than it hurts, you should do it anyway. And an economist would point out that pure property rights don't work in the first place, because of market failures like public goods, common goods, information asymmetry, natural monopolies, etc. So everyone is better off if we violate them at least a little.