I think you missed his point. In places like Alabama, nearly everyone will have an accent. The implication being that anyone with a southern accent, which can

I think you missed his point. In places like Alabama, nearly everyone will have an accent. The implication being that anyone with a southern accent, which can be difficult to understand, would cause what you are terming "dilution". I don't know? My own belief is that making New Yorkers go to school with people from Alabama provides an additional dimension to the education for all concerned. I believe there is value in it. Reasonable people are free to disagree of course.