I don't know about other languages (and I dislike both bashing English and exalting it), but discussions of "why" (and "cause" and "reason") can become confusing unless we clarify whether it's "why" meaning "by what cause?" or "why" meaning "for what purpose?"
In the former sense then, there is some validity to my subject line re. winter celebrations, understanding Christmas to be the adaptation by early (but not the earliest) Christians of Saturnalia.
As for what purpose we might want to imagine that God wishes these days to be celebrated (if at all), we're on pretty iffy ground. It's clear that not everyone in the world or even our country uses them to celebrate anything to do with Jesus of Nazareth. And it's not clear to me that they have to.
When I wish someone well for the holidays my intention is just that, to wish them well, to leave them feeling blessed, not to engage in an ideological campaign. Still for the most part "Happy Christmas" (my preference due to my English upbringing) achieves that, but I am willing to adapt to those who might resent that (few so far in my experience).
There's a certain type of Christian thought I encounter that bashes "political-correctness", which I think falls short both as "Christian" and as "thought".
First of all, PC is itself a disparaging term, meaning that as soon as you use it, there is an intention to insult what it describes. I'm unsure what other term best describes the best intentions of the "movement" (if that's what it is), perhaps "inclusion". Even that sounds bad to some people who fear a slippery slope towards "Our Parent in Heaven".
The problem with PC is not the concern for correctness, by which I here mean calling people what they want to be called, acknowledging that not everyone is part of what we think of mainstream society (ignoring that, by numbers, on Earth that would be Chinese). These kinds of concerns for love (in the sense of respect for others) and truth (in the sense of accurate facts) are worthy of Christians, in my view.
The problem with the PC version of inclusion is that it is *political*. It's about getting votes -- by using the right words in speeches. It's not motivated by sensitivity or concern for truth.
And we are ALL political. Except for that extremely rare person who doesn't care what anyone else thinks (and right now he's probably standing on the corner shouting at traffic), we are all campaigning for approval, votes on the correctness of our ideas. Politics guides the writing of our sermons and of our newsletters.
And of course in churches we learn to speak the prevailing Political Correctness of wherever we find ourselves. And in some settings the Correct view Politically is to bash Political Correctness.
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PS My brief time in Germany was fascinating in this regard. Germany is very secular, but school December plays focus on Christ's birth. It doesn't seem to help much (but I suppose things might be worse without it.) As I like to say "Keep Christ in Weihnachten!".
(Roman Catholics might well urge us to "Keep the Mass in Christmas".)
My suggested stanza for Adam Sandler:
"Jesus may have been God's Son-ukah,
But Jesus celebrated Chanukah!!"
christmas