> Free markets are when people are free to trade with whoever they want to, at the price they both freely agree to.

Except the numerous exceptions where that isn't true. I can't engage in insider trading. I can't get a child to give me his lunch money in exchange for a lollipop. I can't deal heroin. The point being that markets aren't absolutely free, they're free within the limits of what we deem to be culturally and politically acceptable. If you look at the logic surrounding the end of slavery in 19th century Europe, much of the debate was about the property rights of slaveholders and how they ought to be compensated for their lost property.