let me review my last comment:
For the father analogy to be inline with the practice of the watchtower, you'd need this to happen:
1) Father tells his kids not to speak to his ex wife.
2) One of the kid, Johnny, talks to the mother anyway.
3) Father stops talking to that kids.
(the above is not a nice scenario, but nothing abusive).
4) Father than goes to the other kids and forces them to shun Johnny. If you speak to Johnny, I will disown you.
Number 4 is in line with what the WT does and that, even for the father, should be held for harassment in court.
The point is: If the punishment is me taking the personal decision to shun you, well, that is legal. If the punishment is : I will destroy your social circle, that is illegal.