Personally I welcome their involvment.
Wild places are going fast and will be a scarse resource in the future. So, it makes sense to invest in it as a commodity! For many African countries it might very well be one of its most precious commodities, aprart from its human capital!
The peace parks foundation was featured in the September issue of National Geographic:
http://magma.nationalgeographic.com/ngm/data/2001/09/
01/html/hm_20010...
Harry Oppenheimers legacy also lives on with the opening of the Harry Oppenheimer Okavango Research Center HOORC in Maun Botswana:
http://www.ub.bw/departments/centres/hoorc.html
and due to the Oppenheimers inclination the Kalahari Conservation Society was formed, one of Botswanas most prominent NGO's.
I suggest the original poster go after the billionairs without a concience ...
I'll just disregarde the rest of the accusations put forward in the original mail.