Seems consistent to me: Ubers don't want to places where they can't easily pick up a return trip; same as cabs. That's always been my assumption, anyway.
This is a result of poor logistics on the part of Uber and Lyft. There are a large number of Ubers and lyfts that will drop off and have to leave the airport without a passenger, meanwhile, you can call you car and be told it's a 10min wait as someone who isn't even on premises accepts the fare.
Sorry, I'm confused now. You stated above that JFK has passengers going both ways - so isn't this exactly the kind of fare an Uber would want to take on?