This is probably JW's favourite biblical argument in support of disfellowshipping:
1 Corinthians 5:11 "But now I am writing YOU to quit mixing in company with anyone called a brother that is a fornicator or a greedy person or an idolater or a reviler or a drunkard or an extortioner, not even eating with such a man. For what do I have to do with judging those outside?
Back in the day, folk would sit around a table and dip into a communal feeding bowl using either fingers or bread and tuck in. A very intimate thing to do, a sharing experience for all concerned. Somewhat different to eating off one's own plate with one's own knife and fork as we do today!
Back in the day, mixing in company with someone included a firm embrace, often accompanied by a "holy" kiss. A very intimate thing to do, a sharing experience for those concerned. Somewhat different to the simple and polite "hello" with which civilised persons acknowledge one's own existence these days.
So what about Paul's apparent condemnation of fornicators, idolaters etc?
JW's don't appear to understand the meaning of the word IS and Paul's use of the suffix -ER which transforms a verb into a noun. They need to understand that Paul's use of the suffix -ER is applied to serial practisers of sexual sin, coveting, idolatry, slander, drunkeness or extortion). Thus one who has done these things maybe just once or twice doesn't qualify for the big -ER tagged on the end, nor does the Scripture apply to one who NO LONGER PRACTISES these things. Once you've stopped a thing, the -ER suffix is stopped too. Once you've ceased to fornicate, you are, at worst, an ex-fornicator. And this was the whole point of Paul's edicts - to stop doing the things that were frowned on! As simple as that!
Paul therefore makes it clear by his use of the suffix-ER that his recommendation to avoid certain persons only applies to avoiding HABITUAL offenders!