Why do people kill elephants?
They trample the crops that the villages need to survive so the humans want to kill them because if they have no villages, they will not be able to plant crops or live in a safe place.
Eat/drink all of the resources from the land.(water, fruit from trees and plants)
There is a set amount of resources that can be shared amongst the humans/animals, so if there are lots of elephants around and reproducing; the humans will want to kill them so that they don't eat/drink all of the resources.
They also want to kill elephants because of culling(poaching)