If mugabe's gang would be the ones that would starve, I would agree with you. That is not the case however.
Mugabe's deliberate objective is to destroy agriculture, kill by starvation all who oppose him, and finally kill off the useless mouths who do not contribute to his wealth and power.
The only people he needs alive are his thugs, and the people who are needed to work the mines
If he destroys agriculture, then the people who are left will be totally dependent on imported food, which will be under his control. He will then be able to rule forever.