Manhattanite Snobbery

As I was addressing envelopes to soap opera casting directors in Manhattan and Brooklyn today, I considered how offensive it must be to Brooklynites that their address doesn't end with "New York, NY."

Why is Manhattan "New York, NY," while Brooklyn and Queens are either the borough name or the neighborhood name (Sunnyside, Kew Gardens, etc.)?

I have to look this up. I'll let you know if I find anything out.