Its because japs dont have a culture of banter and this is their first exposure If you watched comedy animes you'd know that its mostly a bit of creative irony but mostly kindergarten potty humor so their immediate response is lukewarm insults and basic racism which....uh....yeah. My primary diagnosis of the Japanese mental framework is as follows 1. They are kind of ignorant 2. They are extremely curious 3. Their communicative registers are more primed for deep dive conversations than it is for humor 4. Japanese are not really able to discern humor from texts because it falls as deadpan to them because their humor relies a lot on vocal registers I think they are an excellent people to converse and befriend