beta
Sometimes, even when a person is forced to become a monster, the most responsible humane thing to do is end their suffering. Shigaraki has spent his whole life used, conditioned, and brainwashed to think his actions have enough reason and meaning to be justified. He'll probably never understand why his actions were so frowned upon and even if he does he's not going to think anything he did was wrong.
Unless someone can reset him into a child using some plot bull shit, the guy is going to spend the rest of his life like that. (Or the author decides to redeem him which I don't think id possible to do so and make it well written) So I think it's best for them to end him.