America is a nation of immigrants, which means people bring culture from their country of origin. Unlike other nations, most of which have a homogenized ethnic makeup, America has people from all over. Even taking ‘whites’, there is a fair amount of diversity: Irish, British, French, Polish, Italian, Eastern European, etc. Those groups didn’t always get along, as those nations and regions had long standing history of their own. Part of the consequence of this great American experiment is that oftentimes there is not national agreement on what behaviors are acceptable. In order to make this nation function productively and have a culture that grows over time, we have a series of umbrella-like cultural guidelines.
None of those are more sacred or more integral to the success of the country than the concept of the American melting pot, wherein people share their culture in the public square, other cultures consume and participate in it, and a cultural fusion takes place which makes something uniquely American. Once this process takes place, everyone in the country can adopt these things as part of the fabric of American life, everyone takes pride in being associated with it, and the group which brought the ultimately successful element is rewarded with glory, prestige and increased acceptance in American society.
Several things have gone through this process and become not only cherished in America, but iconically American. Jimmy Carter once said he wanted not a melting pot, but a beautiful mosaic. The endpoint of that concept is similar to what cultural appropriation would create: groups which don’t intermingle, segregate themselves into specific territories, and never unify as Americans rather than hyphenated subgroups.
Jazz, for instance, evolved out of black night clubs from roots in ragtime and became wildly popular. It evolved after African Americans, brought to the United States, learned to play European instruments after culturally adopting European church hymnals. White musicians picked up jazz and created their own twist in the form of Swing music and participated alongside black musicians in the construction of bebop. Jazz, largely pushed forward by African Americans, was a culmination of influences from the African American community and European society; in discovering and advancing this culmination, they created something that was hugely popular and advanced the African American position in society. People respected jazz musicians.