I suppose you are being nitpicky and referring to Christmas Day, Dec. 25th.

You're right, the scene does not take place on that actual day. And neither is Vito's birthday on Christmas Day. The reference is that Vito was born (at least according to the scene) on December 7th.

Still though, it is December and Christmastime.

Apples & Oranges.

Apple

A wise and frugal government, which shall leave men free to regulate their own pursuits of industry and improvement, and shall not take from the mouth of labor the bread it has earned - this is the sum of good government.

- THOMAS JEFFERSON