Durance was one of the people who created the Godhammer Bomb.
The Godhammer Bomb was a bomb that not destroyed matter, but also souls.
Tech that interacts with souls is animancy.
We know that Magran approves of animancy.
I can't be the only one who thinks that Durance practiced animancy before the Saint's War, and that his anger towards animancy comes from shame as much as anger.