"Nor should JWs have the right instruct or encourage the shunning of former members on religious grounds."
They have that right as do the Mormons, Amish, etc. However do they have the right to coerce family, friends etc. by threatening that they will be punished even DFed in turn if they don't shun?
In law, coercion is codified as a duress crime. Such actions are used as leverage, to force the victim to act in a way contrary to their own interests. Coercion may involve the actual infliction of physical pain/injury or psychological harm in order to enhance the credibility of a threat.
So it is a a duress crime. The WTBTS is an active criminal association that counts on duress to keep control of it's followers.
Going back to the Freedom from religion issue the following statement says it best:
Marian Guinn vs Church of Christ Collinsville is an important case where the courts were definitive, "No real freedom to choose religion would exist in this land if under the shield of the First Amendment religious institutions could impose their will on the unwilling and claim immunity from secular judicature for their torturous acts."
The Organization of American States is even more explicit:
1. Everyone has the right to freedom of conscience and of religion. This right includes freedom to maintain or to change one's religion or beliefs, and freedom to profess or disseminate one's religion or beliefs, either individually or together with others, in public or in private.
So it would seem that there is law that could be applied to a case where a family member could prove that they were punished for not shunning a child or family member. That they were under duress to shun a family member and in fact suffered accordingly when they didn't.
Seems like a trial about coerced shunning would be a second legal front.
Or put another way 'opening up another can of whoop ass'.