The obvious problem with nihilism is that ultimately everything is ungrounded and there are no moral truths. Some people are naturally altruistic and feel fulfilled when helping others, others are naturally sadistic and feel fulfilled when torturing others. Nihilism means these are fundamentally equal impulses.
This is why humans invented various religious systems and philosophies to provide grounding for absolute moral beliefs. There's also probably an evolutionary factor at work, where nihilistic societies imploded or were outcompeted by confident cultures which believed absolute moralities. This is being seen today in Europe, with nihilistic progressives having few children, supporting mass migration, resulting in being demographically replaced by absolutist muslims.
Yes, there are people who are sadistic but still fear divine punishment like karma or hell.
And religion may be the best way to force them to stop harming others.
But our society prioritise freedom.
We don't arrest suspicious people without warrants, allow people secret and secure communication on the Internet (I mean I'm not sure those things will continue but still), and even freedom of religion itself.
We should accept the risk of increased immoral activities due to not forcing people religious restriction just because they are born in such family or culture.
And I think society collectively can have morals, especially we are financially and socially fulfilled.
So we need to aim that direction, even though currently it's going to the opposite.
with nihilistic progressives having few children, supporting mass migration
While it makes sense to think that nihilists don't value culture and don't mind mass migration, AFAIK most nihilistic communities are often racist.
Actually most communities, including leftists, don't welcome immigrants.
The only group is the rich and corporations who just want cheap labor while don't need to face cultural conflicts and deterioration of security.
We can restrict migration and still treat current immigrants like humans by electing politicians who aren't sensationalists, greedy populists backed by corporations and continue mass migration after they grab the power.
This is why humans invented various religious systems
BTW, I personally think the biggest factor for religion exploding, especially after social orders were developed and the gap between social classes were polarized, is the anger against unfairness and those exploiting others, manipulating social structures for personal gain, being assholes just because they were born lucky, and facing no consequence.
It's almost impossible to see justice served, or be rewarded for living humble and honest life.
So we needed to invent "heaven and hell", which brings justice for "us" and "them" after death.
Moral truths are a lesser form of truth. There are truths that bind god itself in every possible universe (modally.)
There are grounded, binding falses/truths from which man cannot escape, things so wrong that to call them "value" wrongs is to try and reduce the universal wrongness of the action.
Actions that are wrong for everyone, even God, god or gods, for all time, in all possible universes.
Value wrongs are different than other kinds of wrongs, we make them for ourselves, they can also be true without a god, there is a lot written on this topic.
But man doesn't need god for absolute truths that govern their lives and weighs their actions to exist, doesn't need god for eschatological consequences, etc.
This is why humans invented various religious systems and philosophies to provide grounding for absolute moral beliefs. There's also probably an evolutionary factor at work, where nihilistic societies imploded or were outcompeted by confident cultures which believed absolute moralities. This is being seen today in Europe, with nihilistic progressives having few children, supporting mass migration, resulting in being demographically replaced by absolutist muslims.