My grandfather who is from VT calls 'outsiders', flatlanders. My dad follows suit. I do too. As a true NH native, I was able to live with a 'Tom Sawyer / Huck Finn' mentality. NH was a true 'Live free or die' state until recently.
I think a flatlander are those that move into the state with the hope of bringing the state up to their 'level of ideology and mentality'. They call it progress.
Thank You for letting us be aware of what you think is right and wrong. I am happy the way things were. Now the NH natives have a big mess to fix.
My Guess is to call 'flatlanders', 'Southern Democrats'.