Couple of things:
What do you mean by “atheism”? To me its a nonsense word. There is no such thing as atheism. There is such thing as an atheist though.
An atheist is someone’s position about a single question on a single topic. “Have you been convinced of someone else’s bad reasons and evidence that the supernatural exists.” To not believe someone’s claim about reality is the default position that everyone starts from until they have become convinced that the other person’s claim about reality is probably true. No, no they have not. That’s it, that’s all it is. Ok, now tell me their world view? Political stance? education level? anything else about them at all that affects their decisions about how to live and operate in life? You can’t, it’s not possible.
Example: Jury members at a trial start off with a default position of assuming the defendant is not guilty and just some random person not involved with this trial at all. They must become convinced, by the prosecution, that the defendant , not only, is the most likely person that committed the crime, but was the actual person that committed the crime. At the end of the trial, the jury members find the defendant not guilty, the jury members remain unconvinced of the claims by the prosecution. They remain atheists for example. Now, again, tell me what their political views are? Their world views? You can’t. It’s not possible. Also, because they were not convinced of the prosecution’s bad reasons and evidence, they concluded the defendant was not guilty. Does that mean they have a world view of “not-guilty-ism”? No, that’s not a thing that exists. Same with Atheism. That’s how I understand it.
There are world views that tend to have more atheists in them, like skepticism and secular humanism, but you can be spiritual and religious and still have those world views as well. Francis Collins, head scientist of the human genome project is a good example of this.
One thing about these nordic countries and japan is that they are all very homogeneous in their culture. There is not a lot of other subcultures that they are in conflict with or political cultures that they are in conflict with. Yes, there are other religious countries that are like that too, but they are fragmented between the sexes and class. That is one reason why religious countries fail. They force women to be property for men and divide up the culture for power instead of allowing everyone to have that power regardless of sex and lineage. One thing that all religions teach is to be subserviant to a dear leader in the form of a government or a church or a personality. That is not taught in secular countries. The people are taught to be one for solving their problems instead of handing it off to a hero to save them. They don’t require a “dear leader” to come save them. They save themselves as a group.