A recent book, Sharing the Prize: The Economics of the Civil Rights Revolution in the American South, by Gavin Wright, argues that the civil rights movement not only gave blacks basic civil rights, but also has a major beneficial economic impact on the economy of the south.
(Note: I have not yet read the book. I am basic my comments on excerpts and reviews.)
Wright notes that, as barriers to participation for blacks fell away, the overall economy of the south improved.
What we see, in other words, is not a redistribution in the name of historical justice, but an integration of black workers into the regional economy. When we consider that the civil- rights movement opened the South to inflows of capital, creativity and new enterprises from around the world, it becomes clear that most white Southerners were also long-term beneficiaries of this revolution. From: http://www.bloomberg.com/news/2013-02-13/the-stunning-economic-impact-of-the-civil-rights-movement.html
If the removal of discrimination improved the economy then it seems likely that the imposition of discrimination harmed the economy. That should be painfully obvious to anyone who spends time thinking about it. There were obvious costs to Jim Crow. It cost money to install additional drinking fountains and rest rooms. Clearly businesses lost money by not serving black customers. And clearly it cost money to have a police force that spent time enforcing racial restrictions rather than dealing with crime. It cost time and money for state legislatures to debate and enact racially discriminatory bills.
Discrimination not only cost the subject of discrimination, but it costs those who discriminate. They spend time and money discriminating when they could spend that time and money on more productive things.
If discrimination is bad for an economy then it seems likely that the corollary is true: non-discrimination – openness, acceptance, tolerance – are good for the economy.