You're not going to throw to me, Troy?
While I agree that providing water would have been a nice gesture, it would also have been a costly one for delta or any other airline during such a major weather event. We're talking about JFK here, not Westchester County or even BDL. There were literally hundreds of flights affected so the passenger numbers were undoubtedly in the several thousands. Even one small bottled water per passenger adds up!
And let's just take a reality check here. Have you been to JFK? There are water fountains everywhere. NYC tap water has been rated among the best in the nation. There are plenty of places to buy water if tap "isn't your thing."
This is a perfect example of when travel insurance would have helped. Most policies will pay for lodging and a daily stipend for food and other necessities if you're stranded away from home even when weather is the reason. The OP should call his credit card issuer to see if there was even limited travel insurance just for purchasing the tickets. (That is, of course, if the tickets were charged to a credit card.)