I think BunsenBurner’s conversation C implies that defensiveness is out of line and unnecessary in a friendly conversation. And it is…if you have a reason to know the intent is friendly and if you’re not exhausted from having dealt with that same conversation a dozen other times that day. But I think remaining undefensive is kind of a luxury for people who have not faced much discrimination or trauma or the expectation of explaining your existence for the gazillianth time.
What if you no longer want to call your original home “home”? What if you have struggled mightily to become an American citizen and to be respected as such? What if home has been destroyed by war or famine and you just don’t want to talk about it in a trivial conversation? What if “home” is not a place favored by many Westerners and you just don’t want to deal with the response you almost invariably get? What if you come from a highly cultured background but people tend to assume otherwise by your nationality? What if you were adopted and just don’t feel like sharing private history with a stranger? What if you have no accent at all and your family has already spent generations building the United States side by side with the Irish and the Swedes? I imagine the questions could get old very fast.