Christians believe that Nabi ‘Isa was the son of Allah, and simultaneously Allah Himself. It is thoroughly established that December 25th was not the day of his birth, and most Christians know and acknowledge that. But, they say, historical inaccuracy is not important.
Take note of that. They are acknowledging that factual information is irrelevant to them. They are declaring the supremacy of irrationality in their lives. If facts are so easily dismissed with regard to the most important person in their belief system, is it realistic to expect rationality from them in any other matter?