What I was actually saying is that the same reasons for belief apply whether it’s 2000 BCE or 4000 CE. Humans remain human, and religion fills an inherent need.
There’s other religions than Christianity - large ones - that do not consider the birth of Christ as particularly meaningful. The fact that we’re using it as a point of reference is meaningful - the Christian religion has been very influential - but it is hardly some grand irony you seem to imply.