Let's therefore consider something pathological: let's suppose that a country has a free market in this sense, but is owned in its entirety by a small group, such as how the nobility in Denmark owned something like 90% of the land, while the population are kept as permanent renters, never permitted to buy any land that has been obtained by that group, not due to law, but to traditions of the land owning group. Do you think it would be reasonable to permit trade with such a country?
It's somewhat similar to the situation with democracies, there are many democratic systems. Each favours some over others to at least some extent, the question is whether there is a significant disillusionment among the electorate and an appetite among them for change. As a Brit I don't like the fact that a candidate for President in the US can get a majority of the actual votes, but lose due to the electoral college system, as has happened. An American Might deplore the fact that we don't directly elect our Prime Minister. There are those in each country that deplore these features of their own systems. Nevertheless our respective systems as a whole enjoy broad support among their electorates and that's what matters.
Then engage in dialogue, which requires a shared understanding. It very much matters the definition of free market if you intend to disprove (or more charitably, propose improvements towards) its existence between state actors in the current world stage.