No, the court cannot force association. But the legal entity and its rules falls under jurisdiction of the courts (same goes for the US) and it's not uncommon for disputes within an organization, even non-profits and churches, to be adjudicated in court (eg employment issues - you can't fire someone on illegal grounds such as religion even if you're the Catholic Church)
The rules of the JW organization can be adjudicated by a "worldly" court and often are in, for example, child custody cases. In my case elders were disallowed from disfellowshipping me because it would be prejudicing and damaging to the relationship between me and my child.
There are a number of cases where the actions of the JWs get limited, eg you can get a restraining order against the Watchtower entities from their representatives contacting and visiting you. As long as the court does not limit the constitutional protections, which would be the case of a blanket ban on preaching in a geographical area, civil cases in courts can and do result in all sorts of sanctions on the WTBTS, but the WTBTS often can and does get gag orders in place as well, especially if they end up settling rather than litigating.