Some people today say as a matter of fact that Christians cynically picked December 25 for Christmas to co-opt a pagan sun festival. A minority concludes from this “therefore there is no God,” but that minority draws the same conclusion as readily from alkene reactivity or the parallel postulate. They don’t care any more about geometry than they do about history. But most people aren’t radical atheists or enemies of God, they’re just making conversation, repeating something interesting they heard.
It sounds like the early Christians cared more about the date of Jesus’ conception than in the date of his birth. Some influential writers back in the day thought the world had been created on the vernal equinox 5000 years earlier; that the annunciation was on the vernal equinox and the passover of that year; and that the crucifixion likewise was on the vernal equinox and the passover of that year. They got their date of Jesus birth as March 25 plus nine months. It’s all more complex than that, of course, and it’s an interesting historical puzzle, Hippolytus and the Original Date of Christmas.
The link is from Roger Pearse, who points out we should discuss that dating of Christmas with courtesy, maybe encouraging each other to read more history. About anything is good that leads us to think more about the origin of Christmas.