Russell conwell believed that the primary role of government should be to protect the majority of citizens from the excesses of greedy robber barons?

No, Russell Conwell did not think so. He said the opposite: He thought that people should become enriched as a duty, and that men who are rich are the most honest in the community. He said that 98% of rich men were honest and that's why people trusted them with their money; because these men and their big companies found many people to work with. He said that he sympathized with the poor, but with very few, because their sins had made them remain in poverty, and if they had done evil before God and He had made them poor, were not good people or had many defects.