The whole A plot revolves around cultural appropriation. Bobby tries calling Mr. Yoshida for charcoal. They won't sell to him because he's not Japanese. He tries to grease the wheels by bringing in Chang Wassanasong in person to meet Mr. Yoshida, which Chang clearly declares he's not Japanese. (Nice callback to a prior episode when first meeting Kahn in the neighborhood.)
He goes to meet Mr. Yoshida.
Mr. Yoshida is Black, but he was born in Japan with Japanese parents. Then, Mr. Yoshida and Chang get into a cultural spat about Asian heritage, while Chang is outwitted by the Black Yoshida. 
Next, he goes to an Italian restaurant and does the whole "make an offer he can't refuse" skit. They get mad and accuse him of racism.
Yep, I think Mike Judge has still got it. A White guy, Bobby, wants to make authentic ethnic food, but everybody is giving him shit for it. Oh, now some German critics come into his establishment and lecture him on Bobby's mixed heritage. I never laughed that long from TV before.