This is a statement from the perspective of a Modern American. It implies no understanding of how things looked from a Pre-Christian perspective. Would the Roman's have tolerated people denying or mocking their gods?
Plenty of non-Christian religions have established rules for folks to live by.
Sure. But what is the end result of these other religions? China was more or less unchanged for 3,000 years. They had a belief system, it kept everyone in their place, but where did their society go? Why was it stagnant and content to remain at a medieval level of existence for 3,000 years?
How about the Egyptians? The Incas and the Aztecs? Where did their civilization advance to, and how tolerant of Atheists were they? Would Vishnu worshipers have advanced? Would the Buddihsts have been content to just exist as they did for so many centuries without any change?
The modern world was created solely by the spread of Christianity. All the other religions created stagnant and oppressive societies that never improved. To be sure, there was plenty of oppression in the Christian societies, but the foundation for positive change was there. It was the belief that other people were children of God, and entitled to be regarded as equals, as members of the same family.
Which religion ended slavery? It is still practiced in Muslim countries today. How was it ended? It was that belief that they too are children of God and entitled to a fair treatment.
Your admonition that religions are interchangeable, or that Atheism can exist on a widespread basis without disrupting very fundamental ideas underpinning our society is just naive.
But I am very cognizant of the probability that I will not be able to explain these ideas to you in such a way that you will grasp how this stuff all fits together. I could show you numerous bits and pieces to point you in the right direction, but you will have to do the thinking.
I don’t think society does need to have religious beliefs. Again, there’s plenty of place to ground or moral system that don’t have anything to do with religion. Simple common sense does it for most folks.
One of the most common mistakes that people make is to believe that others think as do they. You speak as if there is only one "common sense" when in fact there are as many opinions on what constitutes "common sense" as there are people.
To people of a certain way of thinking, euthanizing "genetic defectives" is just "common sense." They argue that these people cost money, they will never have a meaningful life, and everybody would be happier if such people were done away with. Here's an example of what I mean about what some will argue is "common sense."
This poster points out how much it costs to take care of genetically defective people,(Erbkranke) and then ends with "It's your money too."
Other "common sense" is that everyone should be employed by the state. That their common work product should be shared from those according to their ability to those according to their need. This "common sense" is responsible for the deaths of 100 million people, and untold misery for the last century.
Whatever are the powers that be, I call upon them to save us all from other people's "common sense."