One can answer your question by considering that the issue of God has always been primarily a matter of deep personal decision, rather than a purely rational cognitive problem.

The Risk of Belief: Personal Choices Between Faith and Atheism

One can answer your question by considering that the issue of God has always been primarily a matter of deep personal decision, rather than a purely rational cognitive problem. As worldviews developed, people adopted the positions that reflected their inner convictions and the degree of trust (or distrust) in reality that they felt. In this sense, both faith and atheism turn out to be products not so much of proofs as of a profound choice, a choice that exposes a person to an inner risk.

As noted in one source, what becomes crucial is the awareness that the question about God concerns not only objective reality but also the "primordial cause, the original support, and the initial meaning" that requires a free, though not arbitrary, choice. It is further stated there:

"Thus, not only with regard to reality as such but also in respect to its primordial cause, its original support, and its initial meaning, one in no way can escape making a free, though not arbitrary, decision. [...] Atheism, like faith in God, is a risk." (source: link txt)

This indicates that even if an obvious deception is later revealed, the basis of the choice was already formed on deep personal convictions. Both positions—faith and atheism—exist as forms of trust or its negation, and their nature is such that convictions become attached to a person not solely on the basis of facts, but also through an internal emotional and intellectual choice. As emphasized in another source:

"There is a God, and there is no God; theism and atheism are two equally arbitrary assertions, two equally unprovable beliefs." (source: link txt)

Thus, before any apparent deception arose, people did not doubt their convictions, since the choice remained deeply personal and did not depend exclusively on external proofs. Even when the "truth" becomes known, this choice proves so interwoven with the structure of a person's worldview that a change in position requires not just logical analysis, but a restructuring of the entire system of values and feelings. This is why, despite the revelations, people continue to adhere to their beliefs—whether in faith or atheism.