Assuming we're talking about Starbucks' Red Cups, let me just say that as a partner for Starbucks, it's ridiculous.
I made a YouTube rant about it (link below), and long story short: Starbucks has never featured any holiday on their cups. If anyone argues that, look at past designs - they may seem more festive overall, but never once has Starbucks featured Christmas or any holiday directly on their paper products.
If you're still offended, may I remind you that Starbucks sells a "Christmas Blend", "Holiday Blend (Kosher)", and Advent Calendars, which are all holiday-oriented in their respective rights.
Anyone who argues that Starbucks is anti-Christian is a damned fool.