I'm not familiar with the history of Russia on the 1800s, but at least from other examples of the barbarious label on the map (mostly from Mexico/America and Africa), I get the sense that barbarous means small semi-independent populations, either aware of the western world and reclusive on purpose (like Mexico) or just minding their own business and not integrated on the western world (like Africa, and maybe Central Russia). But I really don't understand why eastern Russia got mostly barbarous aside from the main cities. Maybe some historical prejudice against Cossacks and Turkic people?

In any case, we can definitely say that the map is skewed towards the cultural understanding at the time, mostly Euro-centric