The unity our church pursues is the exact opposite of the big society unity which has no spiritual coherence. If we think that our freedom to attend the church of our choice is the only good or even the greatest good, then we have turned the church into a man-made clique instead of the family of God.
Consider this explanation from G. K. Chesterton.
It is not fashionable to say much nowadays of the advantages of the small community. We are told that we must go in for large empires and large ideas. There is one advantage, however, in the small state, the city, or the village, which only the wilfully blind can overlook. The man who lives in a small community lives in a much larger world. He knows much more of the fierce varieties and uncompromising divergences of men. The reason is obvious. In a large community we can choose our companions. In a small community our companions are chosen for us. Thus in all extensive and highly civilized societies groups come into existence founded upon what is called sympathy, and shut out the real world more sharply than the gates of a monastery. There is nothing really narrow about the clan; the thing which is really narrow is the clique. The men of the clan live together because they all wear the same tartan or are all descended from the same sacred cow; but in their souls, by the divine luck of things, there will always be more colours than in any tartan. But the men of the clique live together because they have the same kind of soul, and their narrowness is a narrowness of spiritual coherence and contentment, like that which exists in hell. A big society exists in order to form cliques. A big society is a society for the promotion of narrowness. It is a machinery for the purpose of guarding the solitary and sensitive individual from all experience of the bitter and bracing human compromises. It is, in the most literal sense of the words, a society for the prevention of Christian knowledge.
Chesterton, G. K. (Gilbert Keith) (2011-03-30). Heretics (pp. 77-78). Kindle Edition.