The scripture at 1 st Corinthians is also specific about whom to apply the words to. It says "anyone called a bother" who "is" a wrongdoer. Nowhere does it say to continue such treatment once the person is no longer recognized as a Jehovah’s Witness. Nor does it say to shun a person who has stopped in their course of wrongdoing.
And here is a blurb from the 7-15-1985 WT (p31)
"Aid to Bible Understanding shows that the word “apostasy” comes from a Greek word that literally means “‘a standing away from’ but has the sense of ‘desertion, abandonment or rebellion.’” The Aid book adds: “Among the varied causes of apostasy set forth in apostolic warnings were: lack of faith (Heb. 3:12), lack of endurance in the face of persecution (Heb. 10:32-39), abandonment of right moral standards (2 Pet. 2:15-22), the heeding of the ‘counterfeit words’ of false teachers and ‘misleading inspired utterances’ ( . . . 1 Tim. 4:1-3) . . . Such ones willfully abandoning the Christian congregation thereby become part of the ‘antichrist.’ (1 John 2:18, 19)” A person who had willfully and formally disassociated himself from the congregation would have matched that description. By deliberately repudiating God’s congregation and by renouncing the Christian way, he would have made himself an apostate. A loyal Christian would not have wanted to fellowship with an apostate. Even if they had been friends, when someone repudiated the congregation, apostatizing, he rejected the basis for closeness to the brothers. John made it clear that he himself would not have in his home someone who ‘did not have God’ and who was “not of our sort.” Scripturally, a person who repudiated God’s congregation became more reprehensible than those in the world. Why? Well, Paul showed that Christians in the Roman world daily contacted fornicators, extortioners, and idolaters. Yet he said that Christians must “quit mixing in company with anyone called a brother” who resumed ungodly ways. (1 Corinthians 5:9-11) Similarly, Peter stated that one who had “escaped from the defilements of the world” but then reverted to his former life was like a sow returning to the mire. (2 Peter 2:20-22) Hence, John was providing harmonious counsel in directing that Christians were not to ‘receive into their homes’ one who willfully ‘went out from among them.’—2 John 10. ....
The seriousness of this counsel is evident from John’s words: “He that says a greeting to him is a sharer in his wicked works.” No true Christian would have wanted God to view him as sharing in wicked works by associating with an expelled wrongdoer or with one who rejected His congregation."
Notice how smoothly this is written. The entire article is regarding those that are apostates and those that have disassociated themselves. But then they smoothly work 1 Cor 5: 9-11 in to the mix. Doing so gives the impression that "quit mixing in company with anyone called a brother" is virtually synonymous with 2 John 10. You wouldn't mix in company or have a meal with anyone that Christ tells you not to even speak to......so why would you want to even speak with someone that Christ says you should quit mixing in company with? They finish the article by applying John's counsel to not even say a greeting to "an expelled wrongdoer or with one who rejected His congregation." Yet they have absolutely no basis for applying John's counsel to "an expelled wrongdoer". The only basis they have for applying John's counsel is for exactly what he gave authority for. That is........one who has denied the Christ. Even if you take the Watchtower's liberal view of who qualifies as having denied the Christ (they will say that by denying the organization....you are thus denying Christ therefore anyone who is an apostate or disassociated fit the description)......they still have no reason to apply John's counsel to an ordinary disfellowshipped person. One who rejected his congregation? Yes. An expelled wrongdoer? No. THey snuck it in with absolutely no justification.