Can you define "US-style atheism"?

There is a definite British "cultural Anglicanism", where churches are visited routinely by non-believers who would never step inside during a service. I'm one such non-believer; some of my favourite spaces are churches.

But what makes American disbelief in gods different?

Is it that there are fewer beautiful old churches to visit outside of worship hours, or is it that has become inherently, necessarily militant because the US has, since McCarthy and the Red Scare, inserted performative Christianity into as many avenues of life as possible such that an atheist presidential candidate has to lie to get the job?