Answer: because they were concerned about foreign radicals bringing ideas as Socialism, Communism, and Anarchism invading the United States, especially from southern and eastern Europe.
Explanation:
Many traditionalists were shocked at the social turmoil of 1919. They located the germs of dangerous radicalism in the multiethnic cities teeming with immigrants and foreign ideas. The reactionary conservatism of the 1920s fed on the growing popularity of nativism, Anglo-Saxon racism, and militant Protestantism. This scenario generated new efforts to restrict immigration. An alarmed Congress passed the Emergency Immigration Act of 1921, which restricted European arrivals each year to 3 percent of the total number of each nationality represented in the 1910 census. Many traditionalists were shocked at the social turmoil of 1919. They located the germs of dangerous radicalism in the multiethnic cities teeming with immigrants and foreign ideas. The reactionary conservatism of the 1920s fed on the growing popularity of nativism, Anglo-Saxon racism, and militant Protestantism. This scenario generated new efforts to restrict immigration. An alarmed Congress passed the Emergency Immigration Act of 1921, which restricted European arrivals each year to 3 percent of the total number of each nationality represented in the 1910 census.
Because, predominantly in the agricultural Western region of the United States, the demand for cheap labor was extremely high at the time. The source of this cheap labor were Mexican immigrants.
Germany was expected to pay reparations after WWI. War damaged their country, and left it in pieces. They had very little money to rebuild their buildings and roads because of the reparations.
