According to Randall Munroe of xkcd, the true meaning of Christmas is to find the true meaning of Christmas. That reasoning is so meta that it folds in on itself. Whereas the true meaning of Christmas is a festival to light up the darkness of winter, eat enough carbs and fats to keep us from freezing, and cement social relationships while we have the time because we can't grow crops and build things this time of year. Yes, you will have religious traditions tacked onto those celebrations, because why not? Jesus' birthday was not recorded (that wasn't a thing in His culture), but if you're going to celebrate a date, the winter festival is as good as any to commemorate the momentous occasion. And there's nothing wrong with that. Meanwhile, you'll find similar holidays in other religions for all the reasons we have a celebration around the winter solstice.