I don't think so! I think it's another axe to grind for the self-styled "persecuted" majority.
Here's an informative discussion on the basis of federal rulings concerning religious and secular holiday displays on public property.
It seems most religious displays are allowed on US government-owned property (contrary to many allegations) when they are in a secular context (including Santa and reindeer in a holiday display, for example) and don't represent a tacit endorsement of religion by the government (solely religious displays and deliberately excluding secular content, for example).
Then again, it seems the Bushes have declared "War on Christmas". The White House 2006 holiday card is just out – and it does not once mention the word “Christmas.”