White people in the US have a common identity that people around the world who would be classified as white if they moved here (and lost their origin accent) don't have. It was largely formed by dehumanizing natives, black slaves and Chinese immigrants. Until recently, it didn't include Catholics (Irish, Italians, Spanish) or Slavs, and was deeply suspicious of Germans and other Central Europeans until after WWII.
Europe's cultures are based on shared myths, traditions, practices, and values. "White" culture in the US is based on shared myths about race, shared traditions of racial exclusion of minorities (and guilt over it), and their practices and values are not distributed any differently than any other group that has been in the US for 3-4 generations (a large proportion of US whites are descended from fairly recent European immigrants.)
