[ That's a good question, and one that Castiel neither has an answer to nor has ever considered in his entire very long life. There's a very long and uncomfortable silence before he responds again, to the point where Davesprite could be forgiven for thinking he'd managed to forget about the conversation entirely. ]

He must have had some reason. There is always a reason. Souls are precious and powerful things, and we don't need them to carry out the tasks we were assigned. [ There, that makes sense - doesn't it? He doesn't sound satisfied with the answer, but it's the best he can do. He wishes one of the senior angels were here to ask. They would know better. ]