In 1834, Lincoln had not yet grown out of his atheist phase, but the young Lincoln’s lack of faith in God — and his lifelong disbelief in the divinity of Christ — does not explain his vote. In 1834, a vote against Christmas was a safe, even a conventional vote.

Not a single state in the Union closed its offices for Christmas on December 25 in 1834. Lincoln marked his first Christmas as President, in December 1861, by holding a Cabinet meeting in the morning and a dinner party in the evening. The Lincoln family never had a White House tree and sent no Christmas cards. …

The public Christmas as Americans know it today did not take form until late in the 19th century. George Washington issued a proclamation on Thanksgiving, but he never made any statement about Christmas (or Easter for that matter). The first state to recognize Christmas as a holiday was Alabama, in 1836, but the North and especially New England resisted. Not until 1856 did Massachusetts accept Christmas as a holiday. The federal government took until 1870 to follow.

There’s debate on the point, but it seems that Benjamin Harrison was the first president to allow a Christmas tree inside the White House in 1889.