I believe those who studied it found the stores in question, and society in general, were chock full of Christmas references, but were using the trans-religious greetings most overtly (ie. in ads and on store banners) and thus the imagined war on Christmas.

For Christians, the real answer can be found in the words of Jesus, who was very, very clear on what he thought of crass commercialism, and overt public declarations of faith. He was a big believer in giving (everything you have to the poor), but if your definition of Christian involves following the words and example of Jesus, none of the people demanding the Merry Christmas are Christians.