I like how we know of all these magnificent better options that are never exposed in universe(yes, SWLiHN offered to switch: but either she offered only at the end, and thus is untrustworthy, or they cannot be sure she won't switch sides again).
If they cannot be held accountable for their actions, then there's a strong argument that it doesn't matter what you do to them.
Also, one thing: Theion was the Holy Tyrant, seizing by force his place from another. So, he set the precedent.
What options?