Archaeologists are telling us nowadays that the earliest prehistoric human remains found are those of an African female. Others say that the first humans dwelled on the steppes of Eurasia. Here is my take on American cultural identity. The Native Americans may have come from elsewhere in a remote prehistory, but they were here when the Mayflower arrived, so they have at least precedence in time over the newcomers. Think about the Founding Fathers as ancestors.
Exclusion starts from the moment a group establishes itself and adopts an identity.
We could find many examples, ancient and recent, of power or wealth as instruments of exclusion. Some misunderstandings were the following. Athena is a goddess, not a hero. Olive trees were in history the foundation of trade and prosperity, but that does NOT make Athena a goddess of fertility. That is Demeter, the goddess of grain.