I know this scene is tough and sad to watch, but Thor WAS trying to make a point by doing what he did. I hate that fans have taken this scene as a means to hate Thor's guts and call him a hypocrite. He really WAS trying to help and show Loki that people can change and be more, even Loki. Loki is hardheaded, and this was the only way Thor could get through to him. (I do think he overdid it by leaving Loki there, however. The lesson could have been learned without leaving him in this position.)