inclined Mom's who would push their boys to BYU, and boys themselves who are inclined to limit their exposure to problems, that BYU would get a few difference makers.

I'm assuming your quotes on athlete means black player. I had a friend in Texas who played CB (edit; safety) for Stanford. Great guy, a Baptist I think. Black. Anyway, he is the type that would have considered BYU if he had been recruited by them. I think a lot of the negative stereotypes are overcome with visits, and there are obviously plenty of black kids playing BYU sports.

You find 3 -5 kids every year from the south who see the vision of being a top recruit on campus (and of course getting tons of attention) who can play immediately and make a big difference, and those few kids can have a huge impact.

So I don't accept that BYU can't recruit athletic black protestant kids from the south. They can, and if BYU were in the B12 then we would see them accept scholarships to BYU.