On a more serious note. I believe there was a serious risk of dumping 300+ passengers at JFK without ground transportation or available hotels if the storm had taken a track to dump 24" of snow at the airport.
That being said, the large amount of flights that were cancelled were narrow body and more subject to schedule constraints of each airline. IMHO, the long haul flights should be sent provided secondary plans for lodging are secured at places like YYZ or ORD in the event the forecast weather appears.