It’s not funny if it’s not true. ;^)
Good point.
The best epithets contain more than a grain of truth. The OED explains rather than judges. The term, as I understand it, was originally applied to people from Massachusetts who move to New Hampshire to avoid Massachusetts taxes, and subsequently began to demand that the state and town governments in New Hampshire act and spend like it was Massachusetts. The state and local tax burden in New Hampshire used to be about half what is was just to the south, still they had better roads and schools. Southern New Hampshire is a Massachusetts refugee camp. The Bay Staters are completely clueless, they think the epithet applies to all other Bay Staters, except them.