If your argument was “Japan should adopt German-style laws and give citizenship to children of permanent residents” then I’d say yes, that’s a good idea. Your argument, however, is “Japan has Apartheid, Zainichi can’t use the same beaches as Japanese, are forced to live in segregated areas, have a different set of laws applied to them”. Because that is what Apartheid means. You’re trivialising the concept with your accusation.