I guess the idea is to avoid conspirancy theories about mods sneakily editing stuff everywhere on the boards. If the feature is not needed, it's better not to have it, even if we should be able to trust mods. E.g. I would argue against having a big red button in the mod control panel that instantly deletes the entire forum, even if we know for sure that no mod will ever press that button.Furthermore, I don't see why a function should be removed so that moderators can't abuse it.*shudders* Urgh! That is what programmers call a kludge - a dirty hack which works around an issue without actually solving it. In this case a rather ugly work around for a problem which doesn't currently exist. Clearly the better solution here is not to break a working system.
But in this case I think there are too many valid uses of mod post editing to take it away.