Paul speaks of " not eating " with such a person ie an unrepentant sinner . As l have said before l think this means not sharing the bread and wine with them .
This, he said, is to give them chance to think of what they are losing , which is not being part of an organisation, but their salvation.
So it's for the sake of the person's eternal life , not for the sake of the church .
As has been said you can't bring reproach on God . So the WT basically seems to be throwing people to the lions just to protect itself. Of course if the person then in the due course of time goes crawling back , all well and good. They have distanced themselves from whatever they have done .
Jan