" My contention would be however that truly free societies can only work with capitalism"
capitalism is private ownership of the means of production. This private ownership was originally stolen during the enclosure acts and other acts of economic and political violence. The only way they still exist is more of the same. As the rate of profits fall and capitalism expands it is forced into monopoly and then imperalism. These are inescapable facts of the system. It can never be free because it relies on a government to exist to uphold the ruling class.
On top of that your level of freedom is equal to the amount of resources you can take from others through private ownership of capital. It is literally oppression.
Isn't labor the most important means of production? In capitalism that's privately owned, and in socialism it's owned communal. Not owning your own labor is a form of slavery to me. And why does the rate of profits fall? Do you have any data on that? The way I see it, corporate profits in the US are at crazy high levels when compared to wage growth and GDP growth. Seems that in some sense, capitalism is working too well... And I disagree with your definition of freedom (but that's OK, since it's a definition!). I think you know mine...