Actually they do admit to shunning.
From their FAQ:
If, however, a baptized Witness makes a practice of breaking the Bible’s moral code and does not repent, he or she will be shunned or disfellowshipped.
What they don't answer and spin is shunning of those who left and shunning of family members. While not saying that they don't shun family members, they present one situation where a family member would not be shunned. They say they don't shun ones who drift away but make no mention of ones who da.