This is a petty annoyance, but they seem to be in vogue these days. (Would a Petty annoyance be an aversion to NASCAR? :D)
Anyway, a period of time that once started just after Thanksgiving, and seems to be creeping backwards through the fall, is what the advertising and broadcast media have hung the term “the Christmas season” on.
The term has been used for several hundred years, in Christianity generally, to mean one specific thing that has nothing to do with Rudolph the rubaeorhynchous cervid, tinsel, family ingatherings, or anything else – it’s the twelve-day celebration of the birth of Christ and the doctrine of the Incarnation which it embodies that begins at sundown on the 24th of December and lasts until sundown on the 5th of January, i.e., Twelfth Night. (And it was often the case for those who could afford it to give gifts each day during this period, hence the overdone song about milkmaids, light-footed nobility, collie birds, and gallinaceous fowl nesting in pome-bearing trees.)
I have absolutely no problem with retailers taking advantage of a period when there is motivation for their clientele to do additional shopping – but that does not mean hijacking a term of long if specialized standing and transmogrifying it into a new and annoying context.
And, by the way, what’s wrong with wishing for “Peace on earth, good will to men” on April 23 or June 27, or remembering the importance of family love on February 18 or September 9? Why do those fairly worthwhile goals get relegated to the period of tinsel and wrapped gallimaufry?