It was meant to be a parody of the idea that japanese and koreans get pissed off when you confuse the two. But in reality korean and japanese attributes are a bit different. Crocodiles and Alligators are more obvious. I didn’t really think about it too much but after I researched I realized that Crocodiles are usually more jaggy and Alligators are more smooth. However Crocodiles in general seem to be slimmer and Alligators are huskier. 

So I figure if you call Yana a Crocodile she thinks you’re poking fun at her teeth and the idea that gators can’t be slim.