The absence of black people in any town in the South is an impossibility. Did the writers deliberatly script only white people for the show?
First off, you’re 100% wrong. It is NOT an impossibility because there are NO black people living in the part of Alabama in which I grew up. I mean none. There are a few black folks in the county seat which is in the valley but there are none living up on the mountain which I grew up. The mountain has over 40 towns of sizes ranging from 4,000 up to about 15, 000 people. So, your assumption is wrong. There are MANY towns in the south without black people. Also, you are wrong that there were no blacks in Mayberry. If you watch the people in the background, you’ll see several black townspeople walking down the sidewalk and being a part of town. One that comes to mind right off is when Ed Sawyer, the stranger in town, is being confronted by the towns people out on the sidewalk…that crowd contains at least one black person and maybe more. Of course there’s also Flip Conroy (played by Rockne Tarkington). He was going to coach Opie’s football team on the episode “Opie’s Piano Lesson” #215.