WT quotation from SBF's post:
"The Christian congregation is our spiritual family. When someone is disfellowshipped, he is no longer a part of that family. After experiencing the results of his bad conduct, he may realize his mistake and remember how much happier he was when he had a good relationship with Jehovah and the congregation. This may encourage him to come back to his spiritual family."
The outrageous thing about the WT arguments supporting shunning is that they always present it as someone with 'bad behavior' or 'bad conduct'. Sure, there are examples of people who go off the rails and find themselves in trouble, but the vast majority in my experience are people who don't find the religion satisfying or believable and just want to move on in their lives. This is especially true of young ones who were baptized at an early age when they hadn't thought through the consequences. Later as they reach adult age they start thinking for themselves and decide differently. They do something which breaks some minor WT rule and get disfellowshipped. The shunning policy is a grave injustice.