You make some valid points but it's a shame you spoilt it with "ethnically-homogeneous...Confucian culture". You really should go and do some travelling or at the very least some reading.... your characterisation is profoundly ignorant.
While working on my undergrad I studied Mandarin for two years and picked up a Chinese Studies certificate. I'm an American who has been living in Japan for four years. I've also spent a year in Korea, and just returned from a month in Hanoi. Two weeks in Slovenia (a friend is a Slovenian Army officer) and two weeks in Siberia (way back when I had a Russian girlfriend) for some European exposure too.
So yes....Taiwan/Korea/Japan/Singapore largely conform to East Asian value/social systems, which stem from Confucianism. Go read some Mencius and get back to me. Filial piety runs deep out here.
The notion of filial piety, whilst expressed by confucius, is present in some form or another in _every_ non-western culture however it's the phrase "ethnically homogenous" that is troubling; japan alone has more than 300 differening ethnic groups, tawiwan has a significant aboriginal population and as for singapore whilst the chinese cohort no doubt have some confucian affectations I think it's more than a stretch to place that upon the indian, malay and aboriginal populations. Although you didn't list mainland china it's also worth pointing out the not-insignificant minority ethnic groups within its borders.
It seems that whilst you've obviously travelled extensively within asia given that you are a mandarin speaker I suspect that has lead you to viewing the region through an ethnic chinese prism.