would you ask indian, or tibetian or bhutani or burmese, where are you from when you are in nepal. We dont ask them usually because they look alike and we pretty much know where are they from, due to their look or from their accent. For sure you will ask a foreigner that question after exchange of few sentences. I dont think this is a racial question at all. Yeah, there will be one out of 10 people who might use it racially. But you cannot gernalize everybody because of that 1 percent. If you think that way then you will start finding lot of other thing offensive too.