The threat of such ideas is not to Christianity. It is to the personal self-image of those who know that vast amounts of the rhetoric used by religious leaders is not only objectively unsupportable, but is specifically designed to gloss over that and indoctrinate followers into blind obedience.
Repetition is the most effective way to train the mind to react automatically, without conscious thought. Repetition of simple concepts dominates Christianity. Followers are taught that any attempt by "laymen" to interpret the writings for themselves for example, is a breach of faith which makes them a nonbeliever, an outcast.
Christian leaders who are secure in their faith realize that faith is the most effective way to provide a "moral center" to human decision-making. A great many choices in our lives have no clear, objective right or wrong. Somehow we must decide. Faith, religious beliefs, can provide that "tie breaker".
Beliefs that are simple and unambiguous seem to work well. "Thou shalt not kill" is such a belief that, when adhered to in all situations, brings peaceful coexistence. Exceptions undermine the authority of such a belief however. First is the exception for plants and other animals, primarily as sources of food. It was long ago decided that this "commandment" only applied to killing other humans. Then came exceptions for killing anyone trying to kill us. So far, most everyone is in agreement. Then, however, we move down the slippery slope to it being alright to kill people who potentially might try to kill us in the future and further to people who don't hold the same beliefs we do. Beliefs that require adherence to very specific behavior are fraught with peril.
In modern terms...
Long term strategies are very beneficial.
Micro-managing undermines leadership.
The uproar over "The Da Vinci Code" is micro-managing of the first order. It is short-sighted and undermines the trustworthiness of religious leaders.
Most of all, it exposes leaders more interested in exercising the power to control others than on the wisdom Christianity can bring to heal and strengthen them.