Of course, officially atheistical countries, such as North Korea, are earthly paradises.
That's sort of the point - totalitarian systems which tell you what you're supposed to think instead of inviting you to think are problematic. Whether it's legal - China up until recently, USSR, Malaysia - or cultural - US, the middle-East - systems which oblige you to conform to predetermined ways of thinking build internal pressure and that causes issues. That's why you can have countries which either don't take or don't enforce a stance - most of the Scandinavian countries, for instance - and they simply don't have these issues.
All the things you mention are just human nature, and will happen anywhere, in the name of whatever the prevailing ideology is.
Aren't religions, though, supposed to be moderating that human nature - and yet we see the countries that are best at rising above those baser instincts are typically the least religious.
Otoh, Christianity pretty much invented the nursing profession;
Nursing has emerged pretty much everywhere humanity has been - it existed before Christianity was a concept, it existed after the times of Jesus in place Christianity hadn't reached. The formal, professional western depiction is of Christian origin, yes, but that's because it emerged in an overwhelmingly Christian culture where Christian leadership laid claim to anything and everything - Nursing is much 'part of human nature' as the violence and bloodshed that you tried to liberate Christian philosophy from just a short paragraph ago.
modern representative democracy arose exclusively in Christian countries;
Yet democracy was a development that predated Christianity; Christianity implemented a misogynistic, racist, ableist democracy that post-Enlightenment rationalists have modified and updated. Modern western representative democracy emerged out of earlier, Christian systems which themselves emerged from earlier pagan systems.
Christian countries were the first to abolish slavery;
And also amongst the last. And amongst those the implemented it most severely, most widely, and on an industrial scale.
until the secular welfare state arrived, the welfare state was the church
Until the secular state arrived, the state was the church, and the wealth was the church, and the authority (and it was a jealous authority) was the church - there were no other options.
and there are, and have been for centuries, Christian charities doing a huge amount of good.
Undoubtedly. And there have been Christian organisations doing irreparable harm - the KKK. And there have been Christian organisations with a checkered track record - the Roman Catholic Church, the Salvation Army. It's almost like 'Christianity' is no guarantee of anything except an attempt to accumulate power and authority and wealth and influence - when they are coupled with well-meaning people, that's fine, but when they fall into the hands of authoritarian racists, sexists, homophobes and the like it's an invitation for abuse, and the totalitarian nature of religion lends itself to that abuse spreading.
O.