Wow. This is really surprising. I can't see that ever happening in America.The principle exists in the US where if a 'shunning' by a community impacts upon your business then there is potentially a case to be heard by a court. (eg Bear v. Reformed Mennonite Church, Pennsylvania, 1975). But, you're right, more often civil law isn't keen at all to intervene in cases like this. We may disagree with the parallel drawn about a religious community being like a private members' club, but that is how they have been treated for things like this for a very long time across a number of jurisdictions. A court can't force people not to shun someone.
Will be interesting to see what practical remedy is suggested by the Canadian courts should they ultimately rule in this man's favour.