In his partial defense of the Pope's views on economic policy, Ryan Avent writes:
Neither did economic growth magically free American slaves or end Jim Crow. There was nothing inevitable about the end of institutionalised racism in America, and without the end of institutionalised racism in America growth would manifestly not have led to greater justice and inclusiveness in the world.
Avent is right that economic growth didn't end Jim Crow. But it certainly reduced its effect. One of the main ways around Jim Crow laws was for black people to leave the South. Economic growth created opportunities in the northern United States, attracting hundreds of thousands of black people. This certainly reduced the power and effect of Jim Crow laws.
The Pope, or his ghost writers, writes:
This imbalance [in earnings] is the result of ideologies which defend the absolute autonomy of the marketplace and financial speculation. Consequently, they reject the right of states, charged with vigilance for the common good, to exercise any form of control.
Scott Sumner has pointed out that that's hard to believe given that the Pope claims to be talking about the real world and there doesn't seem to be a country in the world in which "the absolute autonomy of the marketplace" is respected.
But put that aside. Instead, note the irony. The Jim Crow laws were laws that did not respect people's autonomy in the marketplace, did not respect people's right to engage in exchange with each other. Remember that the Jim Crow laws were laws. As W.E.B. DuBois pointed out in Black Reconstruction, the Jim Crow laws made it illegal for black people to go searching for better jobs. If they were caught moving from point A to point B, they were charged with vagrancy. Those laws, in fact, were examples of what governments often do when they want to disrespect the marketplace.