Human beings are usually wrong. How is that an argument for replacing it with some secular mumbo-jumbo which, in the end, borrows central principles from the religion predominant in that geographical area? No one actually believes that everything in the Bible is up for debate. No one. The more figurative parts are indeed up for debate. At that point, we do our best to ascertain the intended meaning. Going to a system based upon utilitarianism isn't an alernative.