Your argument was illegitimate. The question is not which Bible verse did they base it on, the question is what is the process by which you apply. You know perfectly well that in this country everyone has the freedom of religion so obviously they do not require a Bible verse for people who do not see the Bible as the word of God. Instead they ask for a recognized leader in your religion to write a letter. That is the law for everyone. Why would you think there is some special requirement for Christians? Hypocrisy.
Don't try and change what you said, they claimed a religious exemption, therefore you need to see the letter from their pastor. That is the law.
Go ahead and try to ask for the verse in the Quran, let's see how far that gets you.
Muhammed Ali claimed a religious exemption from the Vietnam war and eventually won. Many Muslims didn't. You don't need a verse, you need a letter from your religious leader.