@waltercool
The statement should be the other way around to be anywhere near close to correct.

Forcing people to not follow a religion, soviet style, won't suddenly make them smarter. And you don't gain anything from being isolated from established religions. If someone is unintelligent or simply uneducated, it just leaves their brain open to other false beliefs. The issue with that being that they can very well be unpredictable and more dangerous. You don't know what stupidity someone will invent next and believe it's true. Christianity by contrast is a known quantity.

On the other hand, if someone is intelligent and well informed/educated, it is more likely that they can see when something is blatantly false, and stop believing in it, even if they were indoctrinated into it. And the important thing is, in the process of renouncing such a belief, they learn more, and are better prepared in the future to tell right from wrong. I don't think I would have been able to see the logical flaws and inconsistencies in the entire spectrum of woke ideology if prior I hadn't encountered similar or sometimes the exact same arguments used by radical religious people. It allowed me to quickly identify that intersectional feminism is effectively a secular religion that had the path clear to infect people's brains because they lacked strong belief in an established religion.

Which brings me back to my initial point. A society prevented from following a religion doesn't necessarily give you anything of value. It can very well leave it susceptible to more dangerous beliefs. An old established religion will have been polished by time. A new radical belief/religion isn't, and you can't know how people will react to it.

But that's not to say an atheistic society is always a bad thing. It can be a sign that most people have gone through the process of analyzing religious beliefs and renouncing them. It's just not something you'd be able to assess if it happened by just looking at demographics.

One way I think you could tell between such a society, and one were people were just kept away from religion, soviet style, is if people have a habit of irrationally attacking religious people. I have started seeing some of that, mostly directed at Christians. But I'm not ready to jump to conclusions just yet.