Wow, would you care to even try to explain that one? (Tortured logic is always fun.)A moral economy?
Like one where people make money by honestly dealing with one another? And one profits by providing goods and services another person needs effectively and in a way that makes others voluntarily come to them to get their goods and solve their problems? Think of it. A system if economics where people serve one another to provide for themselves.
And one that self corrects if people act immorally.
Wait, we have one! It's called the free market. So why do we want to install a government that's going to tell us what we can or can't do or how we meet our needs for providing for ourselves or what we have to buy regardless of our choice?
The free market has no morality. Slaves were bought and sold like property in a free market.
People are not property. Slavery has nothing to do with the free market.
If People declare a certain subset of 'people' to be property, yes, slavery becomes an exercisse of the free market.
That would be the same as government declaring everything you earn to be its property. The free market means all people are free to trade their labor for remuneration, not just a subset of them.
You simply want to define slavery as compatible with capitalism. The fact is that it took capitalism to abolish slavery.