Why do some people kill elephants?

Because they're making money in very unethical ways. There are people who aren't able to empathize with other living beings. They don't care, how they make their money. These are greedy people who wallow in apathy or possibly are psychopath's or sociopaths. Thankfully, there are heroes, who are willing to risk their lives, to protect elephants & other endangered species from poachers. Ivory and other animals parts sell for big bucks on the black market and are used for various, sick reasons. Thank you for caring about elephants and animals.