Meh, I'm not vegan but I eat vegan meals reasonably regularly. It's not 1980, it's not a choice between a dozen meat containing meals or a salad anymore. I really don't care about this enough to get involved in an argument so if people say that there was only one meal choice that was not vegan in the MDR, well, okay sure.
In the end the only thing to do is vote with your feet and book elsewhere with a line that has suitable menus.