Nothing justifies wishing death on someone else. Period.
Killing a person can be justified if reality constrains your choices but wishes are by definition free of constraint. The moment you add constraint it stops being a wish.
Wishes can be perfect and you can simply wish for a better outcome.
It’s kinda like the problem of evil, only with regard to wishes, you are god.
Wishing death on a murderer is asking ethics to grade on a curve and makes it so ANYTHING can be justified so long as someone somewhere did something worse or tried to.
This is deeply related to the problem of lesser evils.