FliFast is spot on!
It was the AA crew that upon hearing the latest winds said, " we'll declare an emergency if we don't get 31R". The controller responded with vectors and the arrogant, yes arrogant, AA crew said "OK, we're now declaring an emergency". Not for nothin', but if fuel was so low as to not have time for a go-around and vectors for 31R, then why didn't the crew speak up a lot sooner....."AA is declaring min fuel" to approach control/center. If, as mentioned, fuel was not an issue, then the declaring an emergency on final for 22L and joining an immediate right traffic visual for 31R was waaaaay outta line for that crew/captain. No issues with the call not to land on 22L, but follow the local controller's instructions on the GA, don't jeopardize other aircraft on final for 31R or in the immediate area, go back to approach and THEN state your need for 31R and THEN, if no luck, excerise your PIC authority. I don't see anything wrong with what the JFK controller did, the AA crew.....they need a sit down, big time. If your aircraft isn't on fire, is completely in control, and isn't running on fumes, then declaring an emergency and taking the action they did, without any immediate urgency, is just plain WRONG! I hope the crew get's a long talk with the FAA.