Slavery was the condition in relation to which the free consciously recognized their freedom
Gourevitch is putting down arguments for why the concept of freedom emerged within the institutionalized practices of slavery. Make no mistake, these people weren't interested in getting rid of slavery; they were interested in clarifying their position in relation to slaves, and often why slavery was a necessary condition for some deserving people to be free.
There is a way in which the capacity to define oppression is what drives and clarifies freedom. You see this in contemporary discourse when people say, "Black people aren't chattel anymore, so they are free." Or "Black people can vote now, so they are free."
Forget the economic vulnerability black communities suffer, and the inequality black households face, all of which vivify predatory relations and calcify inappropriate relationships of dependence that are the direct results of racialized formal policy and informal customs.
If you get to define what oppression is, then you get to define what liberation looks like. And since we have vulgar notions of the oppression America metes onto black communities, we have the thinnest, most inappropriate concepts of freedom we can extend to these communities.
By the way, I think the Church figures into one of the biggest cons legitimizing racialized degradation. On any given Sunday in the South, you can find someone telling black people "You aren't really oppressed because Jesus loves you. All of your oppression is temporal, but your freedom is eternal." Or telling White people, "You are not really oppressors because Jesus loves them. All of their degradation is temporal, but their freedom is eternal. So just go on your merry way."
By Irami Osei-Frimpong