Why do many people in Chaoshan like to call people from Jiangxi and Hunan "Laobiao"?

Not just Chaoshan people, people from many places call it this. But they are all called Jiangxi people, not Hunan people. That's because during the Long March, Mao Zedong called a Jiangxi person "old cousin" and said that he had an old cousin from Jiangxi. Later, people from Jiangxi gradually became called Laobiao. Maybe because Mao Zedong was from Hunan, so you have heard people from Hunan are called Laobiao.