People used to kill their relatives when they were old and dying, witness the tribes that used to set their sick, old people out in the winter to die quickly by freezing instead of slowly by "natural" causes.
Why do we put down anials that are suffering but refuse to let a person decide for themselves when it is time to depart?
Oh, yeah, I forgot: Those were the people we used to (so judgementally) call UNCIVILIZED.