John D. Rockefeller and Andrew Carnegie were sometimes called robber barons because of their ruthless business practices and monopolistic control over their respective industries. They were known for driving competitors out of business, exploiting workers, and amassing huge fortunes at the expense of others. Their actions were seen as unethical and harmful to the economy, leading to the negative connotation of being labeled as robber barons. Additionally, they were criticized for their excessive wealth and perceived lack of social responsibility towards the communities in which they operated.
