I feel like you are confusing a lot of things.
1) Blizzard isn't delaying the gifts until after Christmas. Christmas is on December 25th which is when they become active in each region. December 24th (which seems to be what you are referring to) isn't when people open up presents typically, or at least in the US which is what Blizzard bases it off of. Post reference.
2) 24 = Christmas Eve. Correct, which has nothing to do with presents, that is December 25th.
3) "torture the kids... Just send them off to bed after celebrating Christmas, but no presents"
What does that mean? Kids go to bed on December 24th (Christmas Eve), then wake up on Christmas morning and unwrap gifts (December 2th). How are they going to bed after celebrating Christmas with no gifts if they open gifts on Christmas morning? Maybe in some parts of the world they open it on the "eve', but the typical tradition of Christmas is to open them on Christmas Day. Do you start all your New Year Resolutions on New Year's Eve too?