It’s a similar thing with Switzerland and Sweden but even more confusing because the Netherlands doesn’t start with a D. It’s very rare in the English language for a country’s name to not be a part of its demonym. They also share common stereotypes in terms of being educated, North European welfare states. I read about geography quite a lot and I still often mix them up. Similarly, the difference between North and South Dakota is probably obvious to the people living there, but so far as the two of us know they are both exactly the same.