US-based cis-hetero white man here. The data reinforce the impression you get glancing at the headlines or spending a day out anywhere in America observing other men. Dare I say it even reinforces what I know from painful firsthand experience as a man, at the lowest points in my life. I was lucky though, with a supportive family who helped me through the confusing years of early adulthood. You can point to the declin…
What America is seeing is basically the result of a culture that only uses one moral value. Jonathan Haidt believes there is a set of moral primitives that all our brains support[0]. All other moral values or rules can be explained in terms of these. He also says that the US (potentially excluding the south) is the most single moral on earth. Particularly the "Liberal Cities" and particularly Universities. That one moral is care vs harm.
Some people want to be particularly moral. In societies the various morals have balanced usage, people will pick different morals to exemplify. Since different morals can give contradicting judgements on the same issue, this results in the net effect of these people being fairly neutral.
In a society with just one moral, all these people end up pushing in the same direction. If society is moving in one direction, then these people need to keep advancing in order to remain particularly moral. Given some specifics of US history, we see this result in the social justice movement we've seen in the last 10 years.
> what explains the relative stability in post-Christian Europe?
Europe, with a few exceptions, hasn't gone as hard at being focused on just a single moral value. They are largely biased towards care vs harm, but still use the other moral values.
[0] - https://en.wikipedia.org/wiki/Moral_foundations_theory