Answer:
It is because the Progressive Era (1890s-1920s) in US history was a period of intense social and political reform. Progressive reformers sought to expand the regulatory power of the federal government in order to expose corruption, eliminate unfair business practices, and improve society. Progressive reformers shared a faith in the power of government to redress social ills and a belief that human nature could be improved.
Industry tycoons like John D. Rockefeller and Andrew Carnegie had been criticized for amassing vast quantities of wealth at the expense of the working man. The Progressive Era witnessed the rise of labor unions, which sought to promote the interests of workers against the powerful business, corporate, and banking magnates. Other advocacy groups arose in this period to demand protections not just for labor, but for women, children, consumers, and the natural environment as well.
These muckrakers were journalists and novelists of the Progressive Era who sought to expose corruption in big business and government.
The work of muckrakers influenced the passage of key legislation that strengthened protections for workers and consumers.
Some of the most famous muckrakers were women, including Ida Tarbell and Ida B. Wells.