Maybe they, like many conservatives, realize that these godless based shenanigans are being integrated into the culture and are slowly being FORCED onto everyone. There is a saying in the Bible - " A little leaven leavens the whole lump." God is talking about sin. Maybe Coulter and Falwell recognize that these Godless rituals, slowly forced upon us, will lead us to being a much more Godless society.
And how are they being forced on everyone? I don't know anyone who celebrates it, I haven't gotten a single Kwanzaa card, haven't seen any Kwanzaa decorations, nothing. Let those who want to celebrate it, celebrate it. And those who wish to leave it alone, then let them leave it alone. But unless those who are celebrating it start questioning the legitimacy of Christmas then I don't see any need to criticize their holiday. Except to get people's mouth's foaming.