In December there are three holy days that are of note (regarding this subject). The memorial of St. Nickolaus, Dec 6th; The Solemnity of the Immaculate Conception, Dec 8th; and the Solemnity of the Nativity, Dec 25th. In the Americas, particularly among Hispanics, the Feast of Our Lady of Guadalupe, Dec 12th, is also very popular. But the presents and all are typically associated with Epiphany, January 6th.
I bring that up because the children usually will receive candy and what we call "stocking stuffers" on St. Nickolaus day. And the Christmas presents are, in several cultures, distributed on Ephiphany (commemorating the Magi bringing presents to the infant Jesus). The Solemnity of the Nativity is a huge thing, but it is moreso a huge RELIGIOUS thing rather than a huge party thing.
Probably what they were talking about was the Feast of Our Lady of Guadalupe, Dec 12th. Very briefly, what that commemorates was the apparition of the Virgin Mary to a converted Aztec Indian named Juan Diego. I'm sure if you work with Hispanics, you've seen the image of Our Lady of Guadalupe on their pickup trucks and all over the place. That image, miraculously, appeared on Juan Diego's tilma (cloak). It is still preserved in the shrine built in Mexico City to commemorate it. The significance was that before that time, the Spanish missionaries had minimal success in conversions but afterward there were floods of converts. So, in truth, the significance of that holiday is the conversion of the Americas to Christ.
Yes, you are right that the Solemnity of the Nativity is far more significant, obviously. But the conversion of the Americas (specifically the Aztecs) is nothing to sneeze at.
Especially if I considered myself a downtrodden people, I'd tend to boogie heartily at the commemoration of my people's conversion through an amazing act of Love on the part of God.