If they want to be sheep, they will be fleeced. If they can't accept reality, they will live in their delusions.

There will always be someone who will take advantage of that ignorance.

5. another reason?

Hedging your bets, like people who won't talk to Jehovah's witness but always buy the watch tower from them, or the War Cry from the Sally Army.
JUST IN CASE the day of judgement is real, and so they can plead mitigation from damnation by saying

I wasn't REALLY an atheist, I was agnostic, I went to the unitarian church and bought these shitty magazines.

I'm not a UU member but I've been to our local one a few times and really enjoyed it. It's very anti dogma/anti fundamentalism, really pretty essentially anti Christianity in many respects. Seems more focused on exploring all kinds of philosophies, recognizing that each takes their own path to greater understanding, whatever that may be, wherever they may find it. The speakers were usually non religious university professors (often what draws me there is the speaker or content being discussed) and it has always felt way more life a philosophy class than a church. I love learning different perspectives, so that's why I've gone before.

I don't know about big cities, but in small rural communities most folks simply go to the same church their parents attended without very much thought about why and how plausible the teachings are. It's a semi-social group where everyone knows everyone else; good music, fellowship, local gossip, last night's ball game, good fishing, golf scores, pot luck suppers and other "important" information is exchanged before and after the services. Logic and reason are pretty much out the door, the preacher tells them kinda what they want to hear, but I don't think small churches are too much into any type control or deception. Perhaps the evangelical type churches are more radical than the mainstream liberal churches. Not "liberal" in the political sense, because I would guess that even most small congregations would lean to the right.

I doubt that it started that way but it quickly became that way right up to today.