Let's be reasonable---the NYC group is not anything like other CS groups.
In Berlin, or Cologne, or Buenos Aires, or Florence (where I've had a LOT of couchsurfing experience) the gender balance / country balance is good, and there are a lot of activities.
I've had great experiences with the Philadelphia CS community, as well. The one NYC event I attended was filled to the brim with "pickup artist" types.
I've been to a couple events in NYC, and while the new york skeezeball types are there, there were other nice people (mostly the foreigners) to talk to, so I enjoyed it.
The DC community is huge - transplant cities will lend themselves to social networks full of strangers, and especially in a capitol city, so in a way it's perfect. But the changes to the website absolutely destroyed the way the community interacted. Nearly everyone has fled to Facebook and phone trees.
In the end, it's all about what you're trying to get out of it. I stopped going to happy hours and dance clubs and started going out hiking, biking, skiing, road trips, etc with CSers and it's been much more rewarding.
In Berlin, or Cologne, or Buenos Aires, or Florence (where I've had a LOT of couchsurfing experience) the gender balance / country balance is good, and there are a lot of activities.
In NYC, it was boring creepy skeevy men.
Dunno why.