[Retric]

Israel is “74.2% Jewish, 17.8% Muslim, 2.0% Christian, and 1.6% Druze. The remaining 4.4% included faiths such as Samaritanism and Baháʼí as well as "religiously unclassified", the category for all who do not belong to one of the recognized communities.” So, it arguably has more religious diversity than the US.

The US is largely Christian with no other religion making up more than 2% of the population.

[stevenjgarner]

It depends how you view religion. "The Pew Religious Landscape survey reported that as of 2014, 22.8% of the American population is religiously unaffiliated, atheists made up 3.1% and agnostics made up 4% of the US population." [1] Probably the largest unrepresented population in US government, running as an atheist is still considered political suicide.

[1] https://en.wikipedia.org/wiki/Demographics_of_atheism

[rayiner]

America is so religious that a majority of agnostics and 20% of atheists believe in a higher power: https://www.pewforum.org/?attachment_id=29652

But you’re correct that there’s different definitions of “religion” at play. As a foreigner, my observation has been that even secular Americans have internalized much of the belief system of Christianity.

[FollowingTheDao]

And the Protestant and Catholics were at war with each other countless times (For 30 years in one case!) so it's not fair to say they are not one religion.

[Retric]

The same is true of every old religion. Americans generally lump all Muslims into one category, but there are serious divisions, associated wars and ethnic violence.

Even those major groups have fractal divisions. https://xkcd.com/1095/