I don’t think there is anything wrong with people buying presents well beforehand, if they are on a budget - it spreads the cost, plus getting bits and pieces in for the store cupboard, or planning rehearsals for singing events, etc. These are common sense things to do.
I think what irritates most people is the bombardment of Christmas ads well before the day itself, along with shops and garden centres being stocked full of tat well before, and sickly Christmas films showing from the end of August, etc.
These ads, showing the “perfect” Christmas Day, with tables groaning with far too much food add to the stress for many people who feel they are somehow failing if their tables aren’t over laden with food or the base of their tree isn’t full of expensive presents at its base. (Which must be perfectly decorated, of course, with everything colour co-ordinated).
It is commercialism, pure and simple, and detracts from the true meaning of the day, and encourages some to get into debt that they really can’t afford.
It all starts far too early, but Pandora’s box has been opened and it is unlikely to close again.
I love Christmas, but I do not like this over commercialised development aimed purely at making lots of money for lots of businesses.