I think I have stated before that I am not an active Bible student and certainly don't consider myself a Bible scholar. Where the Bible is concerned, I am in that widely varied middle ground between totally ignorant and "steeped in the Greek". Some would claim that my admission disqualifies me from commenting on the Bible or the Christianity that supposedly derives from it.
There are probably several reasons why the affiliates of institutional Christianity want to confine all religious discussion to the words and meaning of the Bible. The most often given reason is that the Bible provides an objective standard by which men can judge right and wrong beliefs and behaviors. The obvious contention behind this reason is that it is quite possible to properly understand and apply the Bible. That all sounds great at first blush, but almost anyone knows that there is no general agreement as to this proper understanding. The multiple denominations attest to the disagreements.
In addition to the above and very likely even more significant to the institutional church, is the evident fact that confining all religious discussion to a debate over the Bible gives the church a great advantage. Probably most would agree that the vast majority of people, including those who attend church and/or claim Christianity as their religion, have never read more than a few lines from the Bible personally. However, despite that lack of personal experience, almost everyone has been exposed to the basic tenets of the church's Bible interpretations. Therefore, in any discussion of the Bible, most people are left on the sidelines, unable to participate actively, but conditioned, none the less, to agree with what is familiar, namely what the church has historically taught.
When someone, like the skeptics for instance, insist on evaluating Christian dogma based on its reasonableness, consistency, and logical implications, the church finds itself at a decided disadvantage. Any effort to focus on the ramifications of what the church teaches always exposes contradictions, convoluted logic, and embarrassing historical examples of church contrivance in all manner of mischief based on its biblical interpretation. It is particularly ironic that the skeptics and atheists, whom the church hates with such obvious passion, so often know as much or more Bible than the church members and even their ministers.
No one is probably totally comfortable without some recognized standard of right or wrong. We like to believe that we act properly in accordance with some concrete measurement and that we can judge ourselves and others on that basis. In reality, though, we must admit that people make their own decision about how to behave based on their particular circumstances and their personal viewpoint at any moment in time. Ultimately then, everyone is governed in their behavior by the standard which exists in their mind and heart. We tend to believe that rules and laws guide and restrain people in their actions, but laws and rules merely suggest and maybe outline consequences. In the end people's actions are governed by a personal standard . An objective, black and white standard of behavior may sound appealing, but reality is actually a function of subjective judgments.
The wildly strident response from the church, that we witness whenever anyone suggests that their doctrine be evaluated on something other than a biblical basis, is very understandable when you consider all of the above. The church is in the business of control and that most definitely includes control over the rules of engagement.