The U.S. government was, to varying degrees, hostile to memebers of the labor movement, including musicians like Paul Robeson, Woody Guthrie, and Pete Seeger. Despite this the smithsonian has recorded much of this music for preservation. Does this represent a change in US government policy, or a tension between different aspects of it?
The Federal Writers' Program of the New Deal Works Progress Administration (WPA) collected folklore including folksongs between 1936-1940, representing one of the most comprehensive efforts of the US federal government to gather oral tradition: the program provided support with various degrees of success for all 48 states. The material is archived at the Library of Congress.
The Smithsonian Folkways Collection had/has been a parallel but less comprehensive effort to gather material. While the Smithsonian is supported by the federal government, its charter makes it a distinct entity.
Efforts during the Great Depression often focused on the labor movement because workers rights - and their plight - were the focus of the time. The FDR administration was pro-labor and many of those hired to collect traditions were unemployed writers and educators who tended to lean left. The times leaned left as well, so it is not suprising to find a government program that sought to collect folksongs, that folksongs tended to be about the plight of the worker, and that those who did the recording tended to sympathesize with the workers.