Country music used to be known as “hillbilly” music. Billboard released its first country chart in 1939, called “Hillbilly Hits.” Though that name lost favor as a pejorative, it left its mark. After country artists started using rock techniques, they created Hillbilly rock, or Rockabilly.
The Dixie Chicks are still de facto “banned” from country music radio due to criticizing President Bush back in 2003. Their music is never played on many country stations.