The reason for this is primarily that many religions don't see people who they see as not believing as having the same value as they do. Non-Christians were seen as less human.
If all Christians were super liberal, open minded and never interfered with another persons's business, their very existence in society would still make atheism consequential.
Most people in the West are aware of the religious demand for no sex before marriage - most atheists reject this purely because they see it as having no moral authority as they don't believe in its source.
From the surviving related religions, a lot of their morals seem to revolve around making neighbors happy.
Do you know how the religion was interwoven with political power/social structure?
Even with some of the "monotheisms"(I'm putting this in quotes, because they're not pure monotheism), belief fought for it's place by suppressing Gnostics and other mystics. We can see that direct experience of God was most problematic to the power of those who wanted to control their beliefs. And if one believed in the wrong god, tough luck, it might mean you were a target.
IIRC, this really only started when Christian Orthodoxy became interwoven with political power. Heresies were seen as weakening the power and the legitimacy of the polity. In the pre-modern world, rival sources of power were seen as dangerous (and often were). This created a striving for orthodoxy which led to further oppressions.
Also possibly a reason why Romans persecuted Christians at times, their refusal to accept the dominant cultural practices were seen as a public undermining of official power.
This is where Confucianism is superior. It demands no belief, has the golden rule, talks of love and gentlemanly conduct, improving yourself morally. It poses no problem being a strong atheist, gnostic theist or a devout Buddhist, because the culture doesn't forcibly try to make it a problem. Why the Chinese family under the Three Teachings could have any mix of those religions being a dominant focus was no problem during times when one of the religions didn't enforce itself and we can see how a family could have an even larger mix of religions and atheism in today's China.
There were some repression of Buddhism, especially Tang Dynasty 9th C.
This is where comparing different 'religions' becomes difficult though. By focusing on where it is more tolerant 'belief' it makes it seem more open minded.
Confucianism was very restrictive, in some ways the ultimate monoculture. The purpose of education was to indoctrinate people into the Confucian culture and their status in society was decided by how well they progressed within this culture. All individual worth was bestowed or revoked by the state. There was no space for heterodoxy as this was a direct challenge to the legitimacy of every important member of society from the bottom to the top..
As an off topic aside, I've seen interesting argument that make the case that Chinese society was so successful in creating stability, that this is why they didn't have an industrial of scientific revolution despite being far more advanced than Europe for the majority of their history. The state only valued practical science and there was no room for an emerging industrial class to drive industrialisation
So you don't see religions that can't understand people having value, who don't believe their dominant narrative as being the problem, but people who at least in part don't have belief in parts of it. The intrinsic value of different religions or skeptics is inherently less.
AFAIK, I haven't been making any value judgements, what I've said was meant to be descriptive, what is rather than what ought.
So your primary objection is against things that aren't monocultures, finding that atheism somehow makes people stand out even though they might fully embrace their culture.
I have no objection, I just don't see atheism as a neutral and inert position, but a belief that comes into contact with other incompatible beliefs.
In a society with no racism, not being a racist has no consequences. In a society which contains racists, not being racist can have consequences.
Were there no theisms, atheism would have no consequences, where there are theisms, and where they have played a fundamentally important role in the development of societies past and present, it can certainly have significant consequences.
Zhendema? What time period are we talking about and what "god" of the Three Teachings do you think the traditional Chinese society had, Confucius, Buddha or even Lao Tze?
Wasn't talking about a literal god. In some societies there is a 'real' god who acted as the philosophical source of social order, not having a god meant something else must play this role.
This is why it is hard to compare atheism and its effects across diverse societies. In one society it may be pretty meaningless and in another it is a rejection of the entire social order. It is comparing apples to oranges.
If you want to compare apples to apples, you need to look at what the social equivalent of atheism would be i.e what stance would challenge the social order.
Why is this even a problem? People tend to follow the morals of their culture and atheists tend to follow the laws of their countries. We see that the amount of atheists jailed is less than various religions by adherents. An apologetic should find this a problem.
Who said it was a problem?
It's just another example of a potential consequence of atheism.
But you can't see how an atheist or actually a person who believes in any other religion than the main religion of a country might see all this as insignificant. When I was at an age barely able to read I certainly didn't think about cultural narratives even though it was certain I lacked God-belief. So this, what you are driving at, was completely meaningless to me when I was an atheist from the get-go. As I or other non-believers had no problems with laws or with the dominant culture you could say that this ivory tower speculation you like to say others engage in, is something you should ask yourself about.
I'm not sure you understand my position.
Most Western atheists are opposed to a role for religion (generally meaning Christianity given demographics) in politics. Do you think that this belief is completely independent from their atheism? Most don't pray either, again independent from their atheism or a consequence of it?
I wasn't raised in a religious household but went to a Christian school when I was 5. Every morning we had an assembly sung some songs and prayed. It was all good samaritan, be kind to people, love thy neighbour sort of Christianity, basically good advice for children.
Sometimes I prayed at home, simply because that's what we did at school, sort of like doing maths or playing the recorder. Once I asked my mum about God/Jesus and she said some people believe and others don't. I decided I was one who didn't so I stopped praying at home and in school it no longer had any meaning for me. I still quite liked some of the songs and stories though, but saw them differently.
I was probably 5 or 6, had no idea what atheism was at that point (and wouldn't for many more years) yet it had a tangible consequence for my thought and behaviour.
I see the 'no consequences' approach as being ivory tower speculation because it thinks at the atomised level of the word abstracted from all context, rather than at the level of a concept that exists in a broader cultural environment. It goes against my personal experience, my experiences of interacting with other atheists, and mountains of historical evidence from Marx to Hebert to Nietzsche to Freud to Comte to Russell.