Also, I would caution you personally against allowing metaphysics or mysticism to cover the sloppy use of language. ‘Religion’ is a terrible word in general. Virtually nobody who uses it has the slightest clue what they mean by it, except perhaps as the term for a vague list of mostly unrelated things. Try asking somebody what ‘religion means’. Half the time you will get nothing, or a vague cop-out; the rest of the time you’ll get a list of things that person happens to have heard are religions. Can you define the word ‘religion’ yourself? In a substantive way? If not, you should be careful before you make the statement that Christianity is not a religion; if so, you should probably lay out the definition clearly before you use it in such a provocative way, or else lead into it with your explanation.