The lie in the statement is not that they DO NOT shun those that no longer preach or drift away; the lie is that this person is regarded as a former witness. We know that a former witness is an apostate. A former witness is one who adamantly professes to no longer be a part of the religion known as Jehovah's Witnesses. A former witness is one who is disassociated and disfellowshipped for no longer believing that this religion is the "truth". These examples constitute a former witness.
Someone fading away is not a former witness.
The wording should say "Although we do not shun those who are no longer preaching, associating with our congregation, or attending our meetings, we do shun those who have officially dissasociated themselves, have joined another religion, no longer identify themselves as a Jehovah's Witness, or those who have been disfellowshipped for whatever reason."