Final answer:
Nativists, such as the American Protective Association and the Immigration Restriction League, discouraged immigration during the Gilded Age by launching hate campaigns and advocating for restrictive legislation.
Step-by-step explanation:
The group of people that discouraged immigration during the Gilded Age were the nativists. Nativists were individuals who aimed to restrict the migration of nonwhites, non-Protestants, Jews, and other 'new' immigrants, particularly from Central and Southern Europe. They held prejudices against these immigrants and aimed to prevent their arrival in the United States.
One example of a nativist group was the American Protective Association, formed in 1887, which launched hate campaigns against Jewish and Catholic migrants. Another group, the Immigration Restriction League, sought to implement a mandatory literacy test as a requirement for entering the country.
The nativists' hostility towards immigrants led to the adoption of legislation curbing immigration, such as the Chinese Exclusion Act of 1882 and subsequent acts. These actions reflected a broader anti-immigrant sentiment during the Gilded Age.