A set of examples:
Taking a bear corpse, using taxidermy to preserve it, then putting inside some machinery. Not generally considered wrong. (Considered wrong by some, but not by the majority.)
Doing the same with a human corpse. Considered wrong by most cultures. Arguably wrong in the abstract by devaluing / disrespecting a corpse. But, not too far off from experiments on a cadaver. How do we distinguish these cases?
Then:
Taking a human corpse. Using energy from a realm inimical to life to animate it. In almost all cases considered wrong. Perhaps permissible in extremis, say, setting off a necromantic bomb in a base filled with evil necromancers and their minions. But, harrowing to any who go this route, giving them terrible nightmares and fragmented personalities. Arguably wrong in that the knowledge of how to animate the dead almost invariably undermines a soul, leaving a depraved shell.
Then:
Taking a human corpse. Using necromantic energies to animate it, and to bind a once living soul to it, leaving the soul in a living hell as it is twisted in perverse and unspeakable ways. Hard to think of circumstances where the result is not wrong: Even as a punishment, an undead with a bound soul is a creature with unspeakable cravings, yet intelligent and able to set in motion the most evil of plans.
Thx!
TomB