This is both still the case today and probably was never the case in the way that I think a lot of people would read that sentence.
Property rights have always been maintained, to some extent, through force. This is the case today. The state maintains a monopoly on violence and uses it to enforce property rights.
It's also true that humans, generally, hold some innate concept of fairness which leads to us generally respecting each others property. The use of violence was only ever to handle the edge cases as a last resort.
And "stronger" doesn't imply that the single physically strongest individual maintained ownership. Humans are social creatures who have always banded together and lended resources and support to individuals they trusted to be the most fair when making decisions. This only extremely rarely was the single physically strongest individual.
You have the argument backwards. Even in the old times one would not go and occupy house in a village or milk others' cows not because of some innate concept of fairness, but rather because of genuine fear of backlash resulting in violence of other villagers banding together.
You can see the same thing in animal kingdom. Territorial animals do not cross into rival territories not because of innate concept of fairness (new leaders happily massacre offspring of previous leader), but rather threat of violence and resulting negative expected value of hunting in rival grounds.
Property rights exist primarily because of force. To some extent states exist in order to apply force on ownership rights
Modern world physical property rights - centred around permanent or fixed term tradable exclusive rights of economic exploitation - bear more resemblance to intellectual property rights than the relatively universal notion that people shouldn't have the stuff they're using taken away from them, as do the practical and moral arguments about people deserving fruits of their labour and being more productive when given exclusivity over them.
But at its heart, the concept of physical property ownership is fundamentally different from IP. The fact that there are hybrids doesn’t change that.
If property actually pertained to owners not being prevented from using things, property law would be a very short set of guidelines entirely approved by the author of Property is Theft.
The fact that modern physical property law is - like IP - almost entirely about creating artificial restrictions on other people's use of stuff and the right to charge for its use obviously changes the concept that actually it's fundamentally different.
Physical property is zero sum. If you take something from me, I no longer have it. IP has zero marginal cost of duplication; if you take something from me, we both have it.
Physical property ownership is nearly universal, and is probably related to the way humans are more loss averse than gain seeking (losing $100 is more bad than gaining $100 is good).
There have been some societies with leased, or even no concept of physical property ownership, but those are exceptionally rare and can hardly be held up as equally aligned with human nature.
IP ownership, however, is recent and very artificial. The idea that any random person is prohibited from singing a song they heard or copying a painting is new to the past couple of hundred years, to the best of my knowledge.
It’s fine to be opposed to both physical property and IP, but let’s not equate the two as far as the history of the concepts goes. They’re very different.