Having been to Japan several times… and actually studying Japanese studies… I can see why you're saying this but it's very superficial. None of the southern "essence" that caused the split & war is there in Japan at this point. Or do you mean it's as if the South seceded, then proceeded to lose anyway due their policies being a natural disadvantage, and then developed, out-northing the North?
What is characteristic of "the American South" here?
When I lived in Japan and was asked "Why are you interested in Japan?", I used to respond "It is the only non-Western country(at the time) where I have seen an extremely high level of technical/economic development and it is interesting to see similiarities/differences". (This is of course, long long before the rise of modern China)
The society is based so strongly on group cohesion and de-emphasis of the individual, the experience of living there is very, very different than the West.
I think that this "deep cultural difference" is what the original comment was trying to get at. Sadly the reference point of "American South" ended up triggering a different (less useful) trajectory for the responses.
Does the American South actually have that kind of group cohesion?
The kind of group cohesion you have in Japan tiday wasn't quite all there during the Meiji era (they'd just come out of a civil war, after all. Then there were also sporadic uprisings for decades after
https://en.wikipedia.org/wiki/Chichibu_incident)
The following may help--- if you think of Othello as a kind of ideal southern gentleman, as the Japanese sort of did
https://www.semanticscholar.org/paper/Othello-in-Tokyo%3A-Pe...
Now a Alt-Dixie readaptation of that adaptation must of course be the story of https://en.wikipedia.org/wiki/Nathan_Bedford_Forrest
(Taiwanese would be negroes loyal to the Cause, and Ainu would be the native Americans)
Presumably the characteristic being referred to is superficial politeness mixed with racism or xenophobia.
That does actually kinda make sense, but it works very differently... the politeness is anything but superficial (even counters the racism and xenophobia to a limited degree, but also hides it, coming out to ±0), and the latter two are indeed present but coded as to be ashamed of rather than proud… (unfortunately the coding of shame is also different and doesn't spurn action).
It actually makes it harder to tackle the discrimination, since it's not openly admitted. Glass walls and ceiling.
(Recommended read: https://en.wikipedia.org/wiki/Burakumin
'There is a "virtual taboo" in the Japanese media against discussing the topic, leading to widespread public ignorance.')