Blacks in Rhodesia were much better off back then too.
Africans and other colonized third world people have a mindset where they would rather live under squalor and extreme oppression under one of their own than under comparative prosperity (albeit as second-class citizens) under "foreign" rule.
The irony is that the overwhelming of Zimbabwe blacks are just as much second class citizens under Mugabe as under Ian Smith's government, since most aren't Mugabe's cronies and many aren't members of his tribe. However, skin color trumps reason in "post-colonial" politics.