Well, free markets don't accrue capital to "those who produce" either; there's a lot of problems in completely free markets. Efficiency can't be achieved without complete information; since nobody is omniscient (never mind everybody), there will be plenty of inefficient allocation of capital not in proportion to production.
Moreover, free markets have no moral content. Quite apart from unrestricted transactions creating injustice, free markets reward scarce resources in high demand. But something being in high demand does not make it virtuous - fashions change with the wind - and nor is there necessarily virtue in rewarding the owners of those scarce resources, which may be sheer luck. As a collective, we only want markets that are free to the degree that they are not also unjust; and that's a much harder problem.
Moreover, free markets have no moral content. Quite apart from unrestricted transactions creating injustice, free markets reward scarce resources in high demand. But something being in high demand does not make it virtuous - fashions change with the wind - and nor is there necessarily virtue in rewarding the owners of those scarce resources, which may be sheer luck. As a collective, we only want markets that are free to the degree that they are not also unjust; and that's a much harder problem.