This card comes from MixedBlessing, who do cards to suit more than one religion (hence the term Chrismukkah). I got this from Wordlab, where there is an entry on the topic.

Meanwhile, the legal expert at crosswalk.com is worried about Frosty the Snowman replacing Christian Christmas carols being the thin edge of the wedge.

bq. Many Arizona public elementary schools’ winter concerts do not have children singing about angels Bethlehem, or the little Lord Jesus this year. Instead, it’s “Frosty the Snowman,” “Winter Wonderland,” and “Jolly Old St. Nicholas.” …

bq. “Once you start doing that where do you stop?” the legal counsel asks. “Do you start correcting children inside your school when they say ‘Merry Christmas’ to one another?” He goes on to wonder whether school officials might actually consider stopping kids mid-greeting to tell them, “No, this is the Winter Holiday season. We don’t say Christmas in this school.”

This is perhaps the separation of church and state of which they (used to) speak.