What is truly corrupting about shunning is that it is supposedly done out of love-- out of a sincere desire to help the lost sheep find their way back into god's arms. The cruelty of telling people that they must turn their back on people they have come to know, love, and deeply care about is staggering. The pain it has caused families over time is tremendous, and often it is a lasting kind of damage that never heals and affects many more people than just those directly involved.
The fact that they say it is done out of love, when it is an act/behavior utterly devoid of love, is a crime. That they proudly present it as an idea borne in the heart of a being that is kind, loving, and generous makes you realize the kind of awful, twisted things that we can be made to believe.