I dunno about that
White Zimbabwean population 1979: 242,000
In 2012: 28,732
Mugabe: "to strike fear in the hearts of the white man, our real enemy"
Mugabe: “The courts can do whatever they want, but no judicial decision will stand in our way ... My own position is that we should not even be defending our position in the courts. This country is our country and this land is our land ... They think because they are white they have a divine right to our resources. Not here. The white man is not indigenous to Africa. Africa is for Africans, Zimbabwe is for Zimbabweans.
*(Meredith, Martin (2002). Our Votes, Our Guns: Robert Mugabe and the Tragedy of Zimbabwe)
(Sidenote: I can’t help but wonder what Zimbabwe’s Khoisan population thinks about the “we were here first” argument)
“Mugabeism sought to deal with the problem of white settler racism by engaging in a project of anti-white racism that sought to deny white Zimbabweans citizenship by constantly referring to them as "amabhunu/Boers", thus enabling their removal from their land.” -Ndlovu-Gatsheni, Sabelo J. (2009). Making Sense of Mugabeism in Local and Global Politics
The drop in population could be explained by other factors, but when Mugabe’s antagonistic ideology is taken into account you can imagine why most of them left after he took power. You mentioned Mugabe’s successor having a white cabinet minister, but that’s not really relevant since Mnangagwa is a different person from Mugabe and has sought to distance himself from Mugabe and his ideas. Overall, Mugabe’s tenure as leader of Zimbabwe paints a very negative picture of race relations no matter how you slice it.
