Basically I would agree on on your conclusion about the tag backcountry. However I think there are a few camp sites also in DK which have no facilities and where access is only possible by non-motorized means, e.g. some remote islands only accessible by small boats (Stor Okseø, og Fænø Kalv) . It is also unclear how far away a camp site have to be from the next road or car parking in order to be considered as backcountry. Maybe the documentation should also be more clear about this. And one last thought, also the tag camp_site=* is to some extent subjective, even though it is more clear than the backcountry tag. From the practical point of view, as a potential user of a camp site I would like to know more about the detailed properties like is there drinking water, toilets, fire wood etc.