The joke is that JK Rowling names her characters offensively.

I've seen this done before with multiple non-existent examples.

This one also uses a Japanese example.

My point is that JK Rowling already named an Asian character offensively. She also has an Irish kid named Seamus that loves blowing stuff up, and a black man named Shacklebolt.

All I'm saying is the joke is now distracting from the source, because there is a real example of using her naming conventions on Asian characters. I'll also say that we don't actually know Cho's nationality, yet I don't have faith in JK Rowling to distinguish between non-European nationalities.

Of course, the longer I talk about it the less funny everything becomes.