why wouldn't they go for 2?
Because they don't need it right now.
If they went for 2 now and missed, it's a 2 point game, and if Carolina scored a TD, it would be a 9 point game on the next NYG possession, which would make it a two possession game.
By keeping the score within 1 points, if Carolina scored a TD now, it'll still be a one possession game.
Get it now?