Something that is germane to the topic is that “East Asian” practically is a valid ethnicity in its own right, once you’ve emigrated to a non-Asian country and assimilated to the point that the grandchildren don’t speak “their” native tongue and are only distinguishable by having epicanthic folds.
Technically, the mother countries may all hate each other, but on the playground, it’s all the same teasing.
(Kids can be quite harsh!)