I think it's just acknowledging the reality that property is a social construct, one that's created by the social contract.
From his discourse on inequality
> The first man who, having enclosed a piece of land, thought of saying "this is mine" and found people simple enough to believe him, was the true founder of civil society. How many crimes, wars, murders; how much misery and horror the human race would have been spared if someone had pulled up the stakes and filled in the ditch and cried out to his fellow men: "beware of listening to this imposter. You are lost if you forget that the fruits of the earth belong to everyone and that the earth itself belongs to no one!"
Taken quite literally, property is armed theft from the commons I guess. Unfortunately, it's tricky to do otherwise in a loosely organized swarm of barely tribal actors, because any peaceful society based on shared ownership will be prone to exploitation by malicious actors. It's basically a very large prisoner's dilemma: the global optimum would be to abolish private property, but as long as there are (enough) people around to exploit the situation for their own benefit (and to the massive detriment of everyone else), we have to stick to a sub-optimal system where everyone is worse off than the optimum.
The Soviet Union had this I believe, at least with buildings, and it didn't necessarily work out optimally.
If I were to design a government from scratch I think it would actually be relatively easy to know what's best nationalized and what's best privatized. Nationalize the things that you do not want to be driven by the profit incentive because they need to be fair and accessible to all (mass transit, healthcare, utilities, communication networks, science), and privatize everything else (entertainment, retail, food, services).
yet:
> Nationalize the things that [...] need to be fair and accessible to all
Should food be accessible to all?
Or is food production privatized because market economies more accurately meet consumer demand?
At the same time, governments do not have a good track record of running the food/ags industry. I guess a system where the government heavily subsidizes it and incentivises domestic production, but lets farmers do their thing is probably as good as we can do?
I think this is globalism rather than free market.
I say the government needs to ensure no one starves (food stamps, soup kitchens, etc. depending on the situation), and all food is safe to eat (it amazes me how well governments do this in most countries today), but otherwise production and distribution should be competitive.
This is a common but simplistic view that ignored e.g. concerns about popular legitimacy and support that often lead to the downfall of strongman regimes. Many people think they can enforce their views of ownership over others, but find that it's not quite that simple when they try to put it into practice. That's why I mentioned the social contract.
The alternative to large-scale force is small-scale theft. Which is not so small-scale when you multiply it across every village and province. Ever been in the middle of a full social breakdown? Or a riot? Anyone who's seen what actual anarchy looks like would beg for some sort of order, even if it has to be imposed by force. It requires a very sheltered understanding of how the world actually works to think that anything good will come from unleashing chaos.