I'm not sure, though, whether you're disagreeing with Arand. His point is that atheism undermines our faith in those matters of the heart, as it were, so secular societies are vulnerable to falling back on those instinctive forms of tribalism. The tribal conflicts would be recast in secular terms, such as Trumpism vs Wokeness, but the point is that they'd distinguish America from secular societies that have more deeply rooted unifying cultures.

And my point is that atheism isn't a major factor there. What matters are all the cultural and historical conditions that distinguish social and antisocial secular societies. Americans are more individualistic than Europeans who live in the Nordic countries, and that's so for lots of reasons having little to do with atheism.

But indeed, religions have historically exacerbated tribalism. The stronger a group feels about its ideals, the more likely that group will fight opposing groups to the death. And religion fires up the tribal imagination.