Isn't it the Nativity fast? Besides, it's fun to throw Christmas music at people as early as possible.
Nativity fast is just prepartion for Nativity, teh Nativity "hasn't happenned yet" (the Orthodox Church in its services make the events we commemorate present, real, it's not just rememering them); I prefer not being fed up witht he carols before the feast, but rather listening to tehm during the 12 festal days and even until the 2nd of February (the Meeting in the Temple feast; that's Polish tradition, both Orthodox and Catholic). I know that in Spain it is (or at least it used to be) consider as something sinful to listen and sing Christmas carols before Christmas.
In Serbia, Poland, Syria etc. carolers (at least in villages) start "carolling season" on the Christmas Eve, by singing carolls and inviting people to the church for the festal service (and also after it, to bring the joyful news that Christ is born)
It's the same as listening to Paschal Stichera during Great Lent. I think it's really impraont thing to learn waiting and then ejoy for what we were waiting, in everything.
But I'm sorry for this off-topic
I'll try to post some links to the carols during the festive days, as I have a very rich collection of them in various languages (and as for Poles, we have one of the heritage of the carols in the world).
That "oh joyful news" is beautiful