Is the authoritarianism and coercion a necessary part of church? Clearly left to their own devices, people aren't self-organizing into social groups very well. And perhaps the silly beliefs are an important marker or side effect of social coercion, and can't easily be abandoned. Even if they're not causal, they are a great indicator that you are truly allied with the group.
Speaking about religion in genera:
Authoritarianism, no. I don't see how that's related. You can have a cohesive group without being a dick to everyone who doesn't conform to the exact letter of every little thing.
Coercion is required on some level but unless you really don't conform to any of the social norms of the group you should be fine. A religion can always structure itself to have a bare minimum amount of conformity and accept anyone above that. Being able to conform to group social norms or at leas minimize when you can't is part of being human.
I might have used a poor word. I certainly didn't mean for authoritarianism to mean "being a dick to everyone." I suppose I meant hierarchical structure, pressure, and control.
As a corollary, imagine the sort of social cohesion you see in the military. With regard to the values the military cares about, there's a high degree of coercion and authoritarianism. So, counterpoints about how you can be whatever religion, creed, political party etc aren't really valid in my mind. You can Muslim or Christian, but you can't ignore a salute, or a command, etc. The values the military wishes to coerce are nonnegotiable.
There can be no doubt that the military is good at systematically building cohesion in troops. I'm just wondering how well social cohesion can work without any of these aspects. In other words, does strict individualism harm social cohesion.