The Brazil (Bra-zil??) story is nothing to do with Brazil being in the Americas. There are stories here of black British athletes winning this-or-that in the Olympics and being described by US media as African-American. The substitution of "Black" is automatic: I think this says something about mental language rather than ignorance of geography.

Many people here do think of themselves with two terms, though usually not with any simple name: the terms Black British and British Asian occur, though more likely people will consider themselves to be English, Bengali, Afro-Caribbean, Welsh, or whatever, and British as well.