China and Japan are different, and Ireland and Russian aren't the same, but in D&D you can find together monsters from different folklores and mythologies, Irish, Greek or Nordic cultures.
Japanase cultural influence is stronger in Western civilitation today, but today we can know more about some Korean fiction. Could you mention any Chinese or Korean franchise more famous than Japanese IPs?
In my city or region we say the expresion "don't sell honey with a vinegar face" (or something like this) to warn against bad diplomacy if you have a goal and you need help by others. If China wants to more culturally influencial than Japan or South-Korea has to show a kind face and can forget past offenses, uninentional or not.
Maybe they are right about annoying stereotypes but if they want to sell their titles in Western market then they will to "sallow toads" ( = put ups with an unpleasant situation) and show us their best smiles while they tell us about their last manhuas and donghuas.
We're talking about a book written in the US, by Americans, for the US market. China had zero input into this. Korea had zero input into this.
I agree, we can find monsters and elements from all sorts of different folklores and mythologies from all over Europe and beyond in the base game. Which is kinda the point. You cannot simply paint all of East Asia with a single brush. And that's what Oriental Adventures does. It tries to pretend that the only culture of note that we need to be aware of is Japanese culture. Nothing else matters.
Do you see the issue now? Like I said, if this was a book about playing in Mythic Japan, then all my issues vanish. I would shut up and go away if that were true. Unfortunately, it's not true. It paints multiple cultures with a single brush, blatantly ignoring other cultures and influences while pretending that that single culture is the only one that matters.