I had to stop reading Isekai and transmigration stories that take place in those vaguely European countries or worlds because of this and historical inaccuracies (and the genres tends to not be impressive anyway). It's sadly common in a lot of fantasy or historical stories disregarding language or origin and its why they're extremely boring and easy to write. I think it's from people assuming it's easy to write fantasy and for historical works people assuming they know about Europe because they watched a vaguely historical fantasy film once and that looked about right to them so they didn't do any research and didn't think they had to either. Currently research is minimal for most writers regardless of genre.Happens in Japanese and Korean media too though it's most obvious in Isekai stories where they bring Japanese/Korean food/products to the peasants of the new, vaguely European, world and are celebrated for their novel ideas.