See, Just like tax time and all the formalities of running a buisiness (I.E. better to start a assumed buisiness name at the beginning of the year to last longer....) and like applying for a new job... no one will hire you till after the new year.

This is the reason for all the banning. It's a new year and maybe Blizzard is going to use this mass ban to calculate the earnings of the upcoming years Battle Chest sales.

Seems logical don't you think?
So much easier to keep records of anything at the start of the new year.