That’s a facile and shallow response, and buys into a popular Marxist trope. You could fairly say that if we were talking about whether healthcare in the US is a “free market.” It’s not a gray area like that. You have one example that flows directly from the central principles of Marxism (the failure of centrally planned agriculture) and one example that contradicts the basic principles of free market capitalism (slavery and colonialism). You can’t have a “free” market with forced labor, or where a colony is forced to sell raw materials to the colonizer and forced to buy finished goods from the colonizer. Pinning colonialism and slavery to capitalism is like criticizing filesystem performance in microkernels based on the Linux kernel as an example. Whatever shades of gray may exist in the definition of microkernel, Linux’s filesystem access does not fall into that debatable area.