@Kaarme
I understand the point. Punishment is a deterrence. "If you do something bad we'll kill you." means no one would work for them, which is wack because they shouldn't be doing bad things. But they wouldn't be much of an Association if everyone considered them barbaric for using the death penalty for everything.
But 'punishing' people for breaking their rules seems more civilized and fair. Even if it's torture. "Because then at least they left him alive." But also it's so bad that you don't want to experience it.
"Just as long as I don't do something so horribly bad I'll get killed for it on the spot, then I can dodge most of the rules. At the very worst, I have to deal with the punishment and then I'll get out and get my revenge." or something along those lines.
Basically, it's politics. It's less about torture for fun and more about the message sent, since no doubt they keep records about their punishments.
But no lie though this was fucking stupid especially in this case. "Put the mage in the room of time and spirit for a thousand years, when magic is gathered by using mental energy. His body ages a month, his mind ages a thousand years. Oh wait, magic is gained by using your mind. I'm sure it won't make him an invincible god monster!"