There is absolutely nothing wrong with Muscadines or Scuppernongs. They just aren't major grape varietals. The major grape varietals in the US are Sauvignon Blanc, Pinot Noir, Merlot, Chardonnay, Zinfandel, Cabernet Sauvignon, and Cabernet Franc. You might throw in Riesling, too, though they like cooler weather. I'm not sure with which part of my statement you say is wrong.
I'm not a cork sniffer because I've never had a desire to be in the cork business. I have studied wines for numerous hours at college-level classes. I have taught classes in wines. I have worked in a vineyard. I have worked in a winery. I have grown Scuppernongs and Muscadines. I have made my own wine in a thermos. I have a friend who makes his own wine in South GA, mostly from Scuppernongs. I can enjoy a $5 bottle of good wine, and I can tell you most any major of varietal of wine by simply seeing it in the glass. I don't recall saying that any wine you may find, produced in this area is shi-ite, though I'm not blind to the fact that we are not in wine country.