Looking at the battle as 'the white population of Zimbabwe against the black population' would be far too simplistic.
Each of those white-owned farms typically had its own onsite village of farm staff, who served as labor and supervisory management of farm operations. The farm staff were culturally and economically aligned with the farmers, and formed the major base of the MDC Party. Had the farmers looked ahead and formed an armed defense system that included their staff, the combination of farmers with their staff would have been unbeatable. It was British disdain for mixing with the locals, and disdain for self-defense, that did them in.