I'm also originally from North Carolina, but have lived in Vermont, New Hampshire, Indiana & Virginia in the US, as well as Portugal (3 years), Lancashire (4 years) and now firmly settled in Cheshire for the past 2+ years.
In 1968, when I first moved to NH, I was in a small grocery, and asked a question. The older man on the till looked at me and VERY loudly, in his exaggerated version of a southern drawl, said "ya'll not from around here, are you?" and then laughed a bit and stared, plus made sure every other customer knew I was 'invading the north'.
My point is, idiots and rude folks are everywhere. Ignore them. Most people who ask me where I'm from want to talk about the US, or tell me where they've been on holiday.
If someone is rude, consider the source, and don't take it personally. The rude person is likely rude to everyone, or is a deluded attention seeker.