Um, it's Catholics who incorporate paganism by their own admission.
If the candles which were formerly distributed at the Saturnalia are now identified with the feast of the Purification of our Lady? What, I ask, is there so surprising if holy bishops have allowed certain customs firmly rooted among pagan peoples, and so tenaciously adhered to by them that even after their conversion to Christianity they could not be induced to surrender them, to be transferred to the worship of the true God?" (Baronius, "Annales", ad ann. 58, n. 77). (as cited in Thurston, Herbert. "Lights." The Catholic Encyclopedia. Vol. 9. Nihil Obstat.October 1, 1910. Remy Lafort, Censor. Imprimatur. +John M. Farley, Archbishop of New York. New York: Robert Appleton Company, 1910.21 Dec. 2009 )
We know that God said not to.
9 When thou art come into the land which the Lord thy God shall give thee, beware lest thou have a mind to imitate the abominations of those nations...12 For the Lord abhorreth all these things, and for these abominations he will destroy them at thy coming. (Deuteronomy 18:9,12, DOT)
Evidently Catholics don't care what God said.