They hate white people. They think white people are somehow the cause of racism (they're not) and they hate how successful literally all nations of white people are compared to the rest of the world, especially to all the shitholes in Africa.

Leftists' "diversity" is a codeword to destroy majority white nations, replacing their population with a mix of any non-white people, destroying the heritage of white people, and ultimately suppressing and "punishing" white people when they're in the minority with bullshit like "reparations", at best.