- expertise to pick the most suitable animal for culling?

- skill to do it as quickly and painlessly as possible?

- oversight to make sure they are acting within the guidelines?
...
But getting amateurs to kill animals is an entirely different thing to industrial processing with oversight.

Those are procedural questions, not questions of principle.
Also, it's the wrong questions.
We're talking about Africa here and countries with a semi-literate population where you have a hard time finding someone to make indoor plumbing work.

In other words, the elephants are going to be killed by amateurs in any case, with the great white hunter almost inevitably being the better marksman (given that the typical game warden's daily wage will buy perhaps 3 rounds of ammunition).
Also, in my experience, concepts like "empathy to animal suffering" tend to be quite underdeveloped in the third world, so while the tourist might care about the elephant's suffering, the game warden probably won't.