Uh ... is it news to people that american nationalism is a very religious belief system?

It isn't to outsiders, I definitely heard this comparison made when I was in school ... which was the 90's.

This also feels more like americans adjusting to having explicit ideological beliefs in the first place, since the decades-long political monoculture is breaking up. There is an interesting religious feel to party affiliation in the US, but nothing particularly exceptional compared to other places. Maybe that's an outsider missing some nuance though.