Why im the hell would.sbinra send Sepbiroth to nibelheim?

This just occurred to me this morning while I had my morning coffee.

The kept partt of Jenova there which caused the most mental damage I believe. Now this could be glossed by by saying they susnt know her effects but ike there is Genesis an Angeal the two beings closest to sephiroth who both had gone off he reservation at that point.

An whay does Shina do with their remaining legendary hero. Send him to the one olqdw on earth tbey shouldn't of