It’s rude but it has a grain of truth. Now it’s silly to think that Kentucky is incapable of producing mind-bogglingly talented people, but you’re far less likely to encounter them outside of probably 3 concentrated population areas. I went to college in Lexington and there are a great deal of very smart, very motivated people and the average person you encounter daily can hold a reasonably intelligent conversation. But in fairness to the comment, head east and you run into populations where the average intelligence is a dramatic departure from the average population of your Madisons or Boulders of the world. How much is nature vs nurture is up for debate but I think you’d be kidding yourself if you claimed it was strictly one of the two and not some combination.