Because, New York, regardless of some of it's problems, is a cosmopolitan city where all meet all and discover that they are fine with the fact that they are who they are. NYC isn't as ridden by the beast of conformity as is much of the rest of USA.
Personally, I love going the The City for its vitality and its diversity. It's wonderful and beautiful and garish and dirty, expansive and enclaved and a microcosm of every single aspect of life on earth dwells vibrantly on Manhattan, in Brooklyn, Bronx, Staten Island and Queens, yes, even Staten Island and Queens. *smile*
I find I cannot live there -- it gets to be too much. But, for me, the trains are close-by and to go to New York is to go to the heart of life.
Nichole