what happened when the whites moved in originally, was the farming methods were massively improved to create the sort of infrastructure that if it hadnt been recently destroyed would have their country in a strong position today.

As for what the native people had "done to them", nothing I would imagine, thats what happens when you invade a country, you take over without the people actually doing anything wrong as such, much like the romans came over here and started building roads despite the fact the english at the time hadnt "done" anything to them to justify such an invasion.
The difference is, we had the sense to build on what we got from the romans, not undermine and destroy it, where as mugabe was too blind to see the good the white farmers were doing for his country.