Everyone has the right to shun whoever they want. This is a fundamental freedom and it would be impossible and unwanted to have the government try to change that.
Think it through, how would it work? How could it be misused?
Be careful what you wish for - one day you find yourself unable to refuse a visit from your JW relatives because hey, YOU can't shun THEM.
Previous writings on this issue:
https://www.jehovahs-witness.com/topic/505320005/right-shun-wrong
https://www.jehovahs-witness.com/topic/5544787176325120/doing-right-thing-making-choice-shunning