Agreed. I have to wonder if there were early provisioning issues OR if a lot more people were claiming allergies/food issues than had reported them in advance.
I've been on a cruise (not DCL, but the way provisioning works is pretty standard across lines) where about halfway through they started running out of regular gluten-free bread, buns, etc. Fortunately they were able to restock while we were in Venice as that line had some cruises leaving from Venice. My server, the night he asked if I wanted cinnamon-raisin bread with my dinner or just skip bread that night, explained that they order about 10% more than the reported gluten-free cruisers, but on this particular cruise there were well over 10% over the people who reported the need ordering gluten-free.
So if a lot of people just go in assuming that everything will be ok (especially on Disney which has such a good reputation for handling dietary allergies/needs), there is a good chance that they can run out. Better to report it and have it recorded so they have more accurate figures.