Oda was feeling very generous to the downtrodden and poverty stricken of the world this holiday season. While the rest of us are fortunate to be spending time with family, opening presents, and enjoying life, wise old Oda Clause knew that Zoroaches, subhumans that they are, have none of these things.
So he wrote a chapter with a few panels of Sanji (uninjured btw) not doing anything, and for these zoroaches it's a christmas miracle that makes up for not having friends, personal hygiene, or any value whatsoever to this earth. When Sanji rolls into action, expect to hear about a lot of zoro fans to be pulling the trigger, and I don't mean firing into the sky for New Years.