I think the heart of the matter is whether moderators’ job is to maximize productive conversation, then whether containment or exile are useful tools for that purpose.
Mods do spin off derails into their own threads. I don’t know whether this was just a derail that was segregated or if it was intended to be an actual containment thread as its title states.
Given the history of this forum and where it comes from, I think there are some posters who believe that containment is an appropriate use of mod power. I can foresee someone trying to contain a poster during their turn as a mod, so I think it’s good to have this conversation before we have the crisis of someone actually trying to do that without a clear understanding of how the forum feels (and to have this discussion without having it influenced by the person being punished).