Few Ideologies and religions carry the message of live and let live. The separation of religion and state is one of the rare ones. Its message is a simple one: Believe what you choose to believe but leave me alone. Don't use government to put your religious beliefs or lack of religious beliefs on me or others.

In Australia the school chaplaincy program violates this. So does the subsidies to religious schools by taxpayer money which comes from people of all religious beliefs and none.

Unfortunately Christianity got off to a bad start. It divided humanity.

Matthew 12:30 “He who is not with me is against me, and he who does not gather with me scatters.

Jesus was intolerant. He made enemies of those who didn’t want his religion.

The Inquisition, Holocaust and other murderous activities carried out by Christians although they were not all solely Christian in inspiration were supported by Christian intolerance.

I know of no figures for the death toll due to Christian intolerance.

Islam also has ‘the truth’, and kills people.

Secular ideologies may be as unreasonable as Christianity and other missionary religions.

Nazism divided humans into Aryans and non-Aryans and thought non-Aryans should be either exterminated or serve Aryans.

11,000,000 were murdered. The 5,000,000 non-Jews contained gypsies, homosexuals, Slavs, dissenters and others who did not fit the Nazi vision.

The Communist Manifesto: “Society as a whole is more and more splitting up into two great hostile camps, into two great classes directly facing each other -- bourgeoisie and proletariat.”

Rather than merely describing a system the Manifesto has divided humanity into two classes at war. It‘s analogous to the way the Nazis divided the world into Aryan and non-Aryan and missionary religion divides the world into believers and non-believers. The result of the Marxist philosophy was about 100,000,000 murders of ‘class enemies’.

Marxism was not secular. It opposed religion.

Divide humanity into good guys and bad guys, and you may get murder. The twentieth century was a time of mass murder. Can we do better in the twenty-first century? Can we live and let live?

I'd like to think so, David. I don't know, though.

We are living in a society that is increasingly suspicious of ideologies, religions and 'isms' of all kinds. While many seem to be saddened by this, I think it is a good thing. Perhaps as a product of better education, perhaps as a result of the 'information age', people are able to develop their own worldviews. While some may hold ideals similar to those of Marx and his followers, few would call themselves 'Marxists'. While some (admittedly, like me) enjoy the spoils of free markets and the accompanying dog-eat-dog world, few would call themselves capitalists. Sure, there are the university boffins who still love to compartmentalise people, but their words have decreasing value. With such a diverse array of personal philosophies and mindsets, we need to live and let live just to survive in our world.

This is good for those who do fall into those categories, too: Christians, Muslims, socialists, etc. In order to get by, they (we) are increasingly forced to accept that others see the world in a different way. We are forced to acknowledge that our personal idea of morality, for example, is just that: personal. I am a practising Catholic. I don't believe in birth control or euthanasia. I don't believe fornication, divorce or any other 'sins' are appropriate parts of life. The reality is, though, that few of my friends see the world the same way. I don't try to convert them, and they don't encourage me to 'stray'. One of my best friends was divorced by the age of 25. I supported her through it and we remain close. We live and let live. Most people I know, Catholic or not, act in the same manner. At the end of the day, if they go to bed with a clean conscience, what business of mine is it if they do things I don't like?

If people grow accustomed to living and letting live, which I believe they do, the 'superstructures' of church and state will have to follow suit.

David asks, "Can we live and let live?".

No David, we can't.

We couldn't a million years ago, we can't now, and in a million years time we'll still be fighting each other.

Eventually, like all species, we'll become extinct. And only then will fighting cease amongst humans.

Live and let live? I would like to think so too, David.
I may be wrong but hasn't that ideal lead to anarchy in the past? Given the human condition and its propensity to not learn from the past (in a metaphorical sense at least) it will do so (not learn, that is) again.
Answer? Some form of regulation.
Problem? The regulators - Church, State, whatever ... always has been, always will.
I agree with your sentiments though.

When our whole system of society (government) is enforced at the point of a gun, how can anyone naively ask to live and let live?

Only when all people stop demanding of others unconditionally can we begin a life of live and let live. It ain't happening in our life time, or ....

Can we start by banning people from going door to door flogging their type of religion.
Live and let live; that is my moto. I don't follow any religion, that is my choice.