NO YOU DON"T HAVE TO BELIEVE IN THE BIBLE TO BE A CHRISTIAN!!!!!!!!!!!!
And yes it is pointless to argue, because you apearently don't know what you are talking about. Have you ever hared of Gnostic Christians or Sufi Muslims? I personaly know Christians who don't belive in the bible, they only belive in Christ through their own understanding, or accept Gnostic text as Authentic and belive the cannonical bible to be corrupt.
I am also a Universalist minister and know differnt Mystic Christians, Pagan-Catholics, and Christians who accept Buddhism and Hinduism teachings. You appearnetly have only met or heard of the other kind. Like I said before, you have a very narrow veiw. You can't fight ignorance with ignorance. Just because the ones you know ignore the Universal message of love that their founder preached doesn't mean you should neglect it also.