Are you speaking of Sunday? You can't be speaking of Sunday. It became the day of worship in the Book of Acts. Saint John Chrysostom addresses this very issue in one of his homilies, actually. For several hundred years there were two days of worship within the Christian church, Saturday (as a Jewish sabbath) and Sunday. People lived dual lives, having one foot in both worlds. It was the situation of the Epistle to the Galatians. Chrysostom and his fellow bishops concluded (like the Apostle Paul) that it was an untenable situation, and argued for Judaism to be dropped. That's how it happened. You assume that people today are worshipping other gods through their holidays. Hannibal maybe is, but in honest truth, he is the only person I know who might possibly be worshipping other gods through any holiday associated with Christianity. I remember a blog on the subject of Christmas that gets to your argument.