Sharing food is natural among people who are close to each other, in the same family or not so close to each other, just because we belong to the same human family after all. Sharing food is a sign of friendliness. Most domestic animals were probably domesticated by sharing food with them. The trouble is that in some instance, it creates a lot of problems.
Elephants like any other animals become habituated to being fed. At the beginning, all is well. They go away. Then, they start demanding food. Elephants have a large appetite and need approximately 100 kg of food per day. Habituated elephants do not roam the jungle any more. As they find food in a particular place, they do not bother any more to explore as they normally do. They destroy all vegetation in their vicinity, accelerating their own starvation.
Habituated elephants lose their fear of humans and try to break into houses in search of fruits, vegetables and cereals. Not all people are welcoming to elephants. To defend themselves or just out of fear people will start screaming, and put their lives in danger. Alternatively, they may take a weapon and harm the elephants.
We have seen such development time after time. Our friend Rivaldo (see our videos) was extremely lucky. He became habituated, and probably went to a house where the tip of his trunk was cut. He was extremely lucky to survive. Without treatment, he would have died. Roberto Carlos was less lucky. A miscreant shot the animal in the leg and the he died of septicemia after weeks of atrocious suffering.
When you feed an elephant, you want to be friendly, but you invariably provoke the premature death of the animal. So never feed elephants.