One need not accept anything on insufficient evidence to find the virgin birth of Jesus to be...?

Does "One need not accept anything on insufficient evidence to find the virgin birth of Jesus to be a preposterous idea" refer to "One need not accept anything on insufficient evidence with which the virgin birth of Jesus can be proved as a preposterous idea"?

Well, the core of the question is that I failed to get its nuance in grammar.

Context:

It is time that Christians like yourself stop pretending that a rational rejection of your faith entails the blind embrace of atheism as a dogma. One need not accept anything on insufficient evidence to find the virgin birth of Jesus to be a preposterous idea. The problem with religion - as with Nazism, Stalinism, or any other totalitarian mythology- is the problem of dogma itself. I know of no society in human history that ever suffered because its people became too desirous of evidence in support of their core beliefs.

-Sam Harris Letter to a Christian Nation