It was almost certainly sarcasm. I have family over there and have rarely gotten similar questions from people here in the States.
Although, it doesn't surprise me as much as it probably should. I live in New Mexico and have had people in the past ask if it's difficult traveling to the US, or what it's like living in another country...
My mum, who is Australian, once received a compliment from someone at a local store whereupon learning of her origins said she "spoke beautiful English." Without batting an eye, she replied "Thanks, I usually speak Australian."
So, the structure of the OP's comment adding in the additional exasperation of "there are other cities?!" definitely strikes me as sarcasm.