It can be said that this characterization, ''robber barons'', is largely justified because of the ways and means used by the industrial leaders to gain more wealth.
The industrial leaders in the 19th century were doing everything they could in order to accumulate more wealth. That often meant neglecting the laborers and their rights, keeping the wages as low as possible despite constantly having increase in profit, using violent methods to prevent having competition. In general, all of that can be put as robbing the people of what they deserved to have, be it wages or opportunities for progress, thus the ''robber barons'' characterization is a very good metaphor and largely justified.
The general consensus amongst the Civil Rights leaders during World War II was that the fighting in World War II would advance the cause of the Civil Rights movement as people would see the paradox of discriminating against the very people who were helping to protect American values by fighting for their country.