In some places in South Africa and reserves in Kenya there is something of a population explosion of elephants, to the point that they are pests or are damaging their environment. Controlled hunting is a way to limit their numbers to conform with the available space and financially support the parks.
Useful article -
http://greatunclebill.hubpages.com/hub/Elephant-culling-in-Africa
Thanks for trying to inject some informed sanity into the emotional hype on this topic.
The fact is these controlled hunting preserves and programs are necessary for the preservation of many of these species. Without them there would be no protected sanctuaries and wardens where herd numbers can be maintained and sustained. The poachers would move in and destroy them.