It's hardly unique to Africa, and the opposite exists, too. People do their best to tear down past accomplishments that were previously hailed as special. Why

It's hardly unique to Africa, and the opposite exists, too. People do their best to tear down past accomplishments that were previously hailed as special. Why? I think it's to make themselves feel better in comparison. They get some kind of happiness or satisfaction from elevating their own ancestors, or degrading others'.