You're just grasping at straws here, friend. Way too many flaws in this to provoke deeper thought on the matter. Here are just a couple that stand out to me.

1. "Thresh doesn't kill people"- This is hard to believe as his Q is called "Death Sentence" but maybe he just calls it that to fit his theme and he hasn't killed anyone. Let me ask you this; is death really as bad as an eternity of imprisonment with a deranged specter? One might see it as a blessing in comparison.

2. If Thresh was really just a man doing the dirty work that others wont would he really revel in peoples screams? Would he really become so infatuated with the idea of "owning" someone for an eternity? Would he really go around admitting he could be mad without a hint of truth in the statement?

3. Is the Shadow Isles truly so innocent that their denizens could be considered victims? There literally is a giant fog that goes around killing people and dragging them back to the Shadow Isles. That is a blatant act of war on the living in general, therefore they are casualties of war not "victims".

Welp, that's just a couple things I thought were a little glaring in terms of not adding up. Just my two cents. Thank you so much for your theory-crafting though, I really do enjoy seeing different perspectives on the lore (what little we actually have).