Leftists are Mis-informed. The top family incomes in United States are all immigrants from Asia, all higher than whites.
So where is the need to pick on whites?
Of course they are misinformed, but it’s more like self-imposed ignorance. They believe what they do because they want to, not because it’s true. They want to think slavery is a white invention that was perpetrated only by whites, when historically Europeans were small players in the African slave trade, and Europeans were often enslaved themselves by others. That’s just one example. There are many others.