It seems that W is having a hard time acknowledging America's Christian heritage. It would seem to me that having the phrase "the year of the Lord" in the constitution would be an obvious artifact of a Christian heritage. And that admitting that that literally was referencing Jesus Christ as Lord without having to argue that our country was created as a theocracy or the constitution was a Christian document, whatever that means. It was a document that laid out the governance for a nation which was overwhelmingly Christian. So much so that they used the generally accepted convention for writing dates that was used in the overwhelmingly dominant Christian culture which was America.
The question follows, why is he so determined to deny our Christian hertiage?
I think it is because he wants to undermine anyone that wants to celebrate it, or God Forbid, work to uphold it, or maintain it.