If Jesus was just cursing the fig tree for the heck of it and it didn't tie into Israel then maybe you can explain these verses. Jesus cursed the fig tree and PRESENTLY it whithered. THEN when the disciples saw the withered fig tree, they asked Jesus "How soon is the fig tree withered away". If the fig tree was already whithered when the disciples saw it, why were they asking Jesus when would the fig tree would be whithered away?
Matthew 21:19-20 KJV
And when he saw a fig tree in the way, he came to it, and found nothing thereon, but leaves only, and said unto it, Let no fruit grow on thee henceforward for ever. And presently the fig tree withered away.
[20] And when the disciples saw it , they marvelled, saying, How soon is the fig tree withered away!