That's fair, it does go into an area that I don't have a very nuanced vocabulary for. For the purposes that I usually talk about, the lines get very blurred. I mean, a lot of people are surprised to find out how rare it is among Evangelicals to read or understand the Bible, but it gets hard to draw a line between religion and ideology when nobody in your religion actually knows anything about it outside of a shared US ideology and a vibe

But then, where you might think they'd be less devoted for that reason, they'll jubilantly agree with Pat Robertson that the people of Haiti brought earthquakes upon themselves via wickedness. An atheistic version of US civic religious would reject that as silly, but would probably still say that it's Haiti's fault for not having been a better-behaved colony that would deserve help. You're probably right that it's a stretch to use the word "religion" to describe something potentially atheistic, but admittedly I usually use the litmus test of "do they implicitly uphold the Doctrine of Discovery?" for whether or not I lump them in with Evangelicals