No knowledge of bone broth is pretty ridiculous, since it's pretty much the origin of cooking any meat. I can't think of any culture that eats meat yet doesn't know of broth.
As for bread... No yeast, sure, that's understandable. However, the "hard bread" we see here is leavened, or it wouldn't have this distinct shape. No matter which method they use to leaven, even if it's not yeast, it wouldn't be hard... It might not be as "fluffy" as yeast-based bread, but not hard... unless it's not fresh - but that would be strange for royal kitchen.
The other recipes are understandable because of culture difference, but those two points are just too much.