It's unlikely that the organized religions will get more sectarian... or is it? I am not at all sure.
It seems true that the growth of science and secularism made organized Christianity feel under threat.
Religion can make it worse. Are you supposing that if people were encouraged to believe in a transcendent reality, and to be encouraged by grand rituals and music and preaching, to love their neighbors, then they would put jealousy and frustration aside?
The theory of cultural bias... is the idea that a culture is based on a particular form of organization. It can't be transplanted except to another variant of that organization.
It is only partly true that religion does more harm than good in society. The community makes God into the image it wants, vengeful, or milky sweet, or scrupulously just, and so on.
