" it's slavery because you don't even own your labor."

You are referring to Capitalism. In the days before capitalism, a blacksmith or a weaver owned his own tools and the profit he made was his own. The land was for use by all, and those who worked hard to use it, profited most.
Then the common lands were stolen from the people by the few, who fenced it off for their own exclusive use, and since then, others must pay rents to those who stole (enclosed) the land - and their descendants and those who bought the rights from them.
Around the same time, the bankers started building factories for the newly dispossessed - so now the blacksmith was working, not in his own forge, but as a common laborer in a factory owned by the bank (the "Capital" in "Capitalism").

Now, the worker is NOT entitled to the products of his own labor - they belong perforce to his employer, who them pays the worker what he feels like, keeping quite a lot back for himself.

We live in a society of redistribution where the land and resources have been distributed to the few, and where the value created by the many has been redistributed to the owners of capital.
Capital they manufacture out of thin air by making an entry in a ledger book.