As a card-carrying heathen, I have no trouble with Christians co-opting the Winter Solstice celebrations to mark the arbitrary date they have chosen for the birth of their savior.

Nor do I have any problem with their message of Peace on Earth and Good Will to Everyone

I do get upset when they express some exclusive claim to the date or the season.

PS

If Christmas is about Christ, then Easter is about Oestra, the pagan goddess of fertility