In this case, it's probably more of a matter of the PM not wanting to 'offend' any non- Christians who might receive the card. To that I would suggest that any who are offended are of the 'professional whiners' category who really need to get a life and get that chip off of their shoulder. I send Christmas cards to my Jewish friends every year (have for decades) and they are not offended; they are delighted to hear from me and they tell me so. They also wish me the best for a Merry Christmas and a Happy New Year. Similarly, they send me Hanukkah cards and I sincerely thank them and wish them a Happy Hanukkah as well. This is a concept called 'getting along with your neighbors and friends' which seems to have become unfashionable for many, unfortunately.
I couldn't agree more. The irony is that it's usually white, middle class people who complain about celebrating Christmas. One local council tried to ban the Christmas lights in Birmingham once. I believe they had to U-turn when hundreds of Muslims, Hindus and Skihs wrote in to tell them to stop being silly.
Besides which, I quite enjoy being wished, 'Happy Eid'.
What's an Eid?