This happens to me a lot. People call me mexican because they think that Cuban is the same thing... I try to tell them, "no, I'm cuban & there is a difference." Also, I get you speak cuban & I have to tell them that in Cuba they do speak spanish. These type of things seem so simple to me, but when I think about it it's like well they don't understand because they have never been around people who are cuban or from a different place.
Because we are a culture that likes to assume things we group people without really knowing the facts. We have never been shown a different culture so to us it is weird. Like in India they do not touch their food with their left hands because the left hand is "dirty".. to us this seems outrageous, but that is because we weren't taught that. To them it seems normal because well, it is.
What is really normal? Is there such a thing?