I'm cruising on fathom (to Cuba) on Christmas, and I'm really hoping fathom just has their regular menu on Christmas (embarkation day). I knew going in I was traveling over Christmas, so I am not expecting special "traditional" stuff. I guess I'm weird in traveling over a holiday and NOT expecting that things will be like at home. To me, not having "the regular" is a big bonus of travel!
Plus "traditional" means so many different things around "Christmas dinner" I think it would be hard to meet those "needs" for all guests. What if ham or turkey isn't your family's tradition?
TBH I wish things that are international like cruises just wouldn't deal with holidays at all - UNLESS they do ALL holidays. I felt really bad for the Canadian crew on RCCL's Brilliance this summer. They had to do their own thing on Canada Day but put up with 4th of July silliness in spite of being on a EUROPEAN cruise - and US people being only a small portion of the ship's clientele as many were NON-US citizens.
But I know I am in the minority.