How Do You Spell New York? Knife, Fork, Bottle and Cork

It has been a long time since I have lived on the Vineyard, so forgive me for asking, but when did the term New Yorker become derogatory? What does it mean to call someone a New Yorker? Because New York is several cities, to say that one person who hails from Park Slope in Brooklyn and another from East 63rd street in Manhattan are equally rude is like comparing persimmons to pineapples.