Here's the thing about that:
It is ultimately a pretty selfish philosophy. Whether or not he is "responsible" for the anarchy following Termeran's death, Hunger is the one who (1) knows it is coming, and (2) has the ability to reduce or prevent the fallout. It is selfish to prioritize a clean conscience over lives that can otherwise be saved. It is selfish to say that Hunger can pick and choose which individuals get moral consideration.
If morality is your driving force, leaving the Planar Delta to its fate is not a great look.
How do you know that Hunger is the only one in a position to know the chaos that would result with his death, and he's the only one with the ability to reduce the damage?
I understand that this choice could be likened to our own choice of Revenge over Freedom, but there's ultimately a limit to how many problems we can juggle at once. The Planar Delta's demise seems in no way imminent, and we can't be the only one who realized their peace relies on the safety of a single person. Hunger is not the only one with agency in the world; we can help them should they actually be in danger.
Seriously, we don't know shit. That the Planar Delta will die tomorrow and not enjoy 20 more years of prosperous rule is pure speculation. If the option said his death was imminent anyway you might have a point, but given the civil strife is the main drawback of the Mitigation I seriously doubt it. There's way higher odds that killing him right now would cause more strife than in any other time.
Additionally, If we die in any way all our polities are fucked too, so what right we have to kill him for that? Is that really a precedent we want to set, one so easily turned against us? You say he's morally reprehensible so it's different; but we are arguably worse given all our Curses. Would you prefer to live with someone personally offensive or live with someone with the Apocryphal Curse? I know which one I would pick. Adorie is certain a hedge against this, but she's too weak to secure her rule without us so the principle problem doesn't leave.
It just feels extremely pointless; twisting the to say vote whose very drawback is the immediate loss of life due to internecine strife is actually the most moral choice is pretty puzzling to me, anyway.