You see, the thing I hate isn't Christmas music as a whole. I adore carols and Christmas hymns. It's the Christmas-themed popular music I can't stand.
Maybe I should explain the difference, although I expect a lot of folks already know: while we all use the terms indiscriminately, a "Christmas carol" is technically a song that's worded and structured as either a lullaby for the newborn Jesus, or a joyous announcement of His arrival. Most carols are very old traditional songs, or started out that way, but there are a few notable modern compositions that achieve a similar feel to the traditional carols, notably "Silent Night."
A "Christmas hymn" is generally addressed to God the Father instead of Jesus, but deals with Christmas themes. It's a hymn for the Christmas season. This does overlap quite a bit with the definition of "carol," especially if you want to bring Holy Trinity semantics into it, but I think calling "O Holy Night" a Christmas hymn is a fairly uncontroversial choice. The fact that it's a great song to sing while caroling doesn't disqualify it.
Christmas popular music, on the other hand… is popular music with a secular-Christmas theme. By "popular music," though, I mean any commercial music product that was originally produced to make money, whether it's "Jingle Bells" or a modern pop megastar's latest charity-fundraiser Christmas album. These songs almost exclusively shy away from older religious elements of Christmas in favor of celebrating secularized versions like Santa Claus and Christmas trees, or generic winter traditions like snowmen, coziness, and winter sports. And, yes, there are a few weird, cursed things like "Deck the Halls" (a traditional Welsh tune repurposed in the 19th century as a Christmas pop song), and there's probably some contemporary-praise artist who tried creating a new, contemporary-praise, Christmas song instead of making pepped-up versions of old Christmas carols and hymns… almost certainly equally cursed.
I should probably clarify that I'm not denouncing the secularization of Christmas. Midwinter celebrations are far, far older than Christianity, and the modern Christmas shopping season is not only a crucial element of late-stage Capitalist society, but also a highly visible example of consumers acting neither rationally nor in their own "enlightened" self-interest, and as such, I'm not going to knock it.
What I object to is the nature of most Christmas pop music. Almost without exception, there's a strong "I heard you like Christmas, so I made you some Christmas with a Christmas, so you can Christmas your Christmas with Christmas while you Christmas the Christmas this Christmas" vibe to this music, and worse, a sense of forced cheerfulness and jollity. It reaches deep down to my hindbrain and makes all my social anxieties say, "Oh, crap, here we go again." Much of it also is obvously just thrown together with minimal effort, expense, or artistic expression, simply as shovelware for a jingle-bell-addled consumer market.
The most heinous Christmas pop songs are formulated specifically to target children. Little children, Mandrake! And despite this, we are all subjected to these songs for up to four months prior to Christmas. Can you imagine what would happen to a sporting-goods store if they habitually played "Baby Shark" and the Barney theme on their Muzak?
While I can say that most of it "just isn't very good," that's a personal opinion and I refuse to claim it's relevant. But I theorize that one more reason I find so much Christmas pop music tedious and irritating is because the concept of a safely non-religious, uncontroversial "holiday season," based almost entirely on subjective feelings and concepts, is too vague, confused, and artificial to truly inspire either artist or audience.
By contrast, most Christmas carols and Christmas hymns were products of the old Christendom society, and the creators and intended audience were shaped their whole lives by European Christendom, whether they believed or not. The subject matter and relevance were powerful to them in a way that it's hard for us to understand today.
There are some anti-Christmas songs I enjoy, but anti-Christmas songs occupy a very precarious niche in the popular music ecology. A song can only be "anti-Christmas" until the Monolithic Secular Christmas Music Juggernaut adopts and assimilates it. We need to learn from what happened to "Fairytale of New York."