In the decades after the Civil War, most streetcar companies in the South discriminated against one class of citizens: smokers. Customers who wanted to smoke had to ride in the back of the car.
Around 1900, many governments in the South passed laws mandating segregation by race instead. As Jennifer Roback documented in the Journal of Economic History in 1986, many streetcar operators protested against this new form of segregation.
Assuming that these entrepreneurs were driven by self-interest alone rather than a desire for equality, why would they do that?