Yes NYC is somewhat different from most other places in the world.

Unlike powered RC planes, gliders are less intrusive as they are quiet and unthreatening. HLGs and DLGs are even friendlier to a city environment. You don't need a runway and you don't need room for a sailplane launcher of any kind. Since there is no motor there is no noise of any kind and no need for some way to recharge a motor battery.

You can fly a DLG anywhere you have some open space. And because the wing loadings are typically low, you can slope soar them on a whisper. I have heard of people slope soaring off of parked trucks with HLG/DLGs. And there are pleanty of water front areas around NYC as the whole city is a collection of islands, so tiny slope spots might be everywhere.

I don't live in NYC, I am on Long Island, east of NYC. Lots of clubs of all kinds out here. If you ever happen by this way again, send me a PM and we can arrange to fly together.