Yeah, I agree. I also don't understand how the mods who responded seem to imply that they don't know who banned who. I would expect there to be a list of banned people so they could potentially unban a person early, which should also include the mod who added the ban.
Even if it doesn't, you'd expect they'd keep some kind of log so they would know to increase the ban duration if it's the Xth time a user breaks the same rule. Even if it's just to have some kind of internal accountability to avoid a mod going rogue. Heck, it could be as simple as a separate mod channel on discord or mod-only thread on the forum.
It's one thing if they don't want to out the person who banned a specific user, it's irresponsible not actually knowing.