Regardless of the origins, it was co-opted by the communists and the leftist labor movement. If we investigate the origins of Christmas Day, we find it is a pagan observance of the winter solstice. Yet the day is, in our time, undeniably the celebration of the birth of Christ.
What matters is not any original association of the date. What is important is the association that folks will make today.
(BTW, you'd be amazed at what people already know on the subject.)