I was never a JW but I have been a part of 2 different churches that did many of the same things. I have shunned, and gossiped about, and judged, lots of folks that the leadership said were no longer any good.
One day I finally was able to leave that demented non-church and realized that most of the things I believed about these people were based on what the "leadership" told me. After I realized that their discernment was really judgement, my wife and I could not believe how badly we had treated people while thinking that we were pleasing God. Just utter nonsense.
We began to call people and appologize. Though people reacted differently, we were amazed how much healing it brought when people are told, "You are not the person we said you were. You did not deserve to be treated that way. Will you forgive us?"
Every single person did forgive us though we are not done. Shortly after we left said non-church, the leaders stood up in front of the non-church members and said that we should be avoided. This was the first time in that non-churches history that someone was shunned from the non-pulpit. This was a little special treat reserved just for us. We took comfort in Matthew 5:10-12
Blessed are those who are persecuted for righteousness' sake, For theirs is the kingdom of heaven. Blessed are you when they revile and persecute you, and say all kinds of evil against you falsely for My sake. Rejoice and be exceedingly glad, for great is your reward in heaven, for so they persecuted the prophets who were before you.
Our big sin was telling people how bad the system was, while we were still in a leadership position. All kinds of evil was spoken about us to people that we really cared about and we are sure that they believed it but we understand because we believed the same kinds of stuff about others when we were under the veil. Since then people have come to us as they left the group and asked our forgiveness and we were able to tell them that we forgave them when it happened.
hth
Carl