I get what you are saying, and if I may ask, what thing did the preacher say you must believe in to be Christian?
I guess for me, Christianity is now an experience as it took me a while to realize that so much that is found in the Bible can be easily disproven. I can see using the Bible to inspire people (when you pluck out the humanist parts) but it is also far too easy to use it to control people. I am finding the WT to be a fine example on how they make scripture say whatever they want it to say. As I have seen pointed out on this board, when something can mean anything it means nothing.
I think anyone who calls themself a believer has a customized religion. How else do we end up with over 40,000 Protestant sects and new churches forming all the time even in the midst of already highly churched towns and cities. This is in addition to the fact that even within the church you have various people who do not always agree in regards to what they believe.