Shunning or loosing a loved one (by means of shunning or being shunned) is not a foreign concept. We shun family members, I am sure all of us do. The essence runs down to the reasons for shunning.
A member of our extended family (wife's cousin) committed murder. He had a wife and several children. The wife worked three jobs while he stayed at home "taking care of the children". The truth is he would drop off the kids with his mother and he would go fuck around. He ended up fathering a couple of more children with another woman and eventually, for reasons unknown to us at the moment, he killed her and burned her. He was eventually caught by the police and is now in jail awaiting trial. We want nothing to do with him at the moment, although I would say that if he ever gets out of jail and happens to come home, with his family for a BBQ, he will be welcomed in. But should not expect any assistance from us at the moment. His family is breaking ties with the rest of us because we don't want to help with the bail.
Shunning someone should be your personal choice, based in your values and belief and not in the values and belief or direction handed down by someone else.