Arguing in such matters mostly doesn't help. You might end up loosing a job or loose image.
You should discuss it in private or in written with your supervisors or directors.
I am sure they can make exceptions for those who fast during Ramadan, since they won't be wasting time on lunch or any coffee drinking, smoking etc.
The company should not give this right to all staff, because not all do fast during Ramadan. This is maybe why they refused it on your first attempt.
I would advise you to talk in private.