I find it so strange which words we translate and which words we transfer. It’s bizzare to me that we don’t often call countries by the same name as the natives do, for example.
My guess is that there are different names for countries and cities in each language because some sounds don’t exist in some languages.
And of course things get even more complicated when poltics are involved i.e. Taiwan vs Chinese Taipei.
I’ve been having a lot of the same doubts about Duolingo as a platform lately. I was an early adopter in 2012, when it first went public, and while it’s never really been a good language learning platform, it at least didn’t feel like it was actively making your language learning experience worse. I’d say in the past year, maybe around the time they introduced “Super Duolingo”, and started messing about with the learning trees.