Gods word says do not even eat a meal with one who was called brother( baptized) then becomes unrepentent. Jesus clearly taught, members of your own household would become your enemies. Matt 10:36) That means they are Gods enemies. One does not associate with Gods enemies. Friendship with the world is enmity with God. James-4:4There is no truth found in an organization that will disfellowship a member that does not adhere to their false doctrines of devils.
My teachers are correct disfellowshipping the unrepentent-- They can still stand back up. Most are to busy pointing the finger everywhere but where it should be pointed at themselves. Its their fault if they get disfellowshipped.
You seem to think its so bad, In the OT for many things, one got stoned to death if they were unrepentent. No chance to stand back up.