This isn't a conservation issue or a conservation failure. This is a public safety issue and a public safety failure. In the Nepalese culture if a human kills another human or multiple humans, according to their own religious and social morays, they can put that person in prison for life, not primarily to discourage others, although that may happen, but primarily to protect the public from future homicides from this individual at the very least.
The first humans killed by the elephant, the elephant has to be accountable for, the elephant must be prohibited from being able to continue this behavior, either by death or confinement. Death penalty for people or animals may not palitable to Nepalese culture, but confinement certainly is. Every person killed after the goverment became aware of the killings and which animal it was, and of that animal's whereabouts, all subsequent killings are not the dumb animal's responsibility, but the responsibility of every individual up the chain of command in the Nepalese goverment who failed to confine the elephant and thus prevent future killings. You could put a 10' x 10' x 10' cube of concrete and in the ground, chain one of the elephant's feet to it, and keep it that way until it died. This would have prevented any future killings without killing the elephant or violating Nepalese cultural constraints. If you think that is animal cruelty, then put a bullet in it's brain and be done with it, which I think is far more humane.
Every Nepalese goverment official who abdacated their responsibilty to public safety and allowed all these subsequent human deaths, should be imprisoned for life, sentenced to feed and pooper scoop for the chained elephant they were so concerned about, and their property sold and funds distributed to the survivors of the elephants carnage. In such a case I would wish the elephant and long life and hearty appetite.
There are concepts such as public safety, accountability, and restitution which are universal and transcend social, geographical, religous, cultural, and political differences.