I've always wondered this as I grew up in SC - but do we know why the character was chosen to be canonically from there? It's an odd and uncommon choice so it stood out to me!
I believe his childhood in SC is
referenced once or twice, but not much more detail beyond that.
That's new for me! I've never seen any references at all that he should have come from South Carolina. When i read the book "Pathways" by Jeri Taylor, I get the impression that he's from California (which always seems to be the center of the Earth in all series and movies, not only Star Trek

).
Some areas, like The South are always overlooked in movies and TV series. Star Trek is no exception and I wonder why. Therefore I find Trip Tucker one of the few good things with "Enterprise".
Robert Duncan McNeill is from Atlanta so I often wondered why they couldn't let Paris be a Southerner.
And there are never any Poles, Czechs, Germans, Hungarians or other Central Europeans in Starfleet. At least not in important roles. No Scandinavians either.
As for Kim, if they didn't want him to be the "stereotypical Asian", then they failed miserably. I mean, they couldn't even decide iof he was Korean, Chinese or Japanese.
I mean, we have a guy which is most likely of Korean-American descent and he constantly comes up with Chinese expressions.
it's like Picard which his French ancestry should constantly come up with: "Now there's an old Bulgarian expression".
