> The point is that Christianity has become so normalized to you that you don't recognize Christian celebration as religious.
So? Doesn't that just serve to lessen its overall religiousness? I mean, Christmas's traditions are themselves derived from pagan solstice celebrations. Wouldn't that make it a pagan institution by your reasoning?
Much like how Christians adopted pre-existing traditions and slapped a Jesus-shaped label on them, people are now slapping a secularity (or, I would argue, consumerist) label on to Christmas traditions.
> Christmas's traditions are themselves derived from pagan solstice celebrations
Well... [0]
> Wouldn't that make it a pagan institution by your reasoning?
Even when, say, a previously pagan practice is incorporated into Christianity, it is reinterpreted and given a new meaning, though probably in some way related to the original _by analogy_. This could be done to help the new converts better relate to the new faith and to preserve as much of the good in the previous culture as possible (in general, Catholicism gladly takes in whatever good and reconcilable there is in any culture[1]). In agreement with what you say, this does not make Christianity pagan.
Whether this is the same as the secularizing or commercializing or "consumerizing" of Christmas, I don't know. Maybe you could argue that this lumpenreligions are doing something analogous to what I just described, but this seems like a flaky comparison. Besides, secularism is a Christian heresy, so it's more like a heretical version of Christmas that's being practiced. The very idea of "secularism" is incomprehensible outside of Christianity (e.g., in Islam there is only Islam and the world of the infidels to be conquered and brought under the rule of Allah; the mosque is not an institution like the Church, just a building for prayer and thus no distinction, much less separation, between Church and State is thinkable).
> The fact that you incorrectly think that the "vast majority of people on the planet are also Christian" proves my point.
No, it means that I confused the terms "majority" and "plurality". If 75% of the world were Christian, it wouldn't make "being human" a Christian institution.
One is not a Christian because Christianity influenced their culture.
> and the vast majority of people who practice xmas are Christian
The vast majority of people on the planet are also Christian. Does that make "humanity" a Christian institution?