I want to preface this with the disclaimer that I don't mean this post to be harsh. The tone can come across poorly because I'm frankly a little peeved that something like this could be controversial, but it's not meant as an attack on the previous poster in any way, shape, or form. I just feel this one reasonably wide-spread misunderstanding needs to be addressed head-on.
"Secularism" has a binary definition in Webster's dictionary: n. the principle of separation of the state from religious institutions.
This is literally (as in people can read it) enshrined in the first amendment to America's constitution. It requires a sideways reading of America to get to the conclusion that high levels of religiosity change the meaning of the English language.
Tolerance in an academic sense typically describes states like the Ottoman empire (the poster child) where the emperor was Caliph but other faiths were tolerated and even given a degree of self-government. The Netherlands would also count as embracing "tolerance," as would Prussia and France for intermittent periods of the 17th and 18th centuries. The Holy Roman Empire after the Peace of Westphalia might also count as "tolerant" since multiple faiths were considered equal although Austria was officially Catholic. In Qing China there was a similar "Eastern variant" of Ottoman or European "tolerance." (This was not true in other Asian states like Japan.) Tolerance means there's a state religion, but if you don't subscribe to it you won't be prosecuted.
It really depends on how we're defining 'Tolerance' vs. 'Secularism'. My instinct was to say that 'Tolerance' implied a state religion / strong religious presence that nonetheless allowed for non-state religions to exist/spread, where 'Secularism' was more like 'No State Religion' / minimal religiosity where faiths exist but marginalized and out of power. Tolerance would includes countries like the UK (from Elizabethan Settlement to present day) or modern Indonesia (Muslim-majority population with constitutional monotheism, though other faiths are tolerated), where Secularism might include the 'state atheism' of the USSR, or the official secularism of modern France.
If that's the spectrum, I'd argue that modern America (and America at its founding) falls far closer to the idea of 'Tolerance' than 'Secularism'. Yes, First Amendment, yes, separation of church and state, but when America was founded, the First Amendment was to prevent the federal/national government from imposing a single state church on the entire country -- most of the 13 original states had some form of state church within their own borders. America is far more religious (by participation) than pretty much any country in modern Europe, and religion has consistently played a much larger role in public life and the national identity than most other places in the First World. That is certainly changing in present day -- church attendance has been dropping for decades and religious symbolism in public life is fading away (cf. Ten Commandments in courthouses) -- but that represents a new phenomenon, not how the country was from its founding.
To address the specific misunderstanding of what secularism is outlines above I want to hit this post point-by-point.
America at its founding had no state religion, and even by one of the binary definition ("No State Religion") given, America would be secular. "Minimum" religiosity is not synonymous with "No State Religion." Religiosity is not a gov't policy. Some colonies did have official religions
as colonies, but the America civ begins with the independence of the colonies, otherwise it would spawn ~1600. To use reductio ad absurdum, we don't spawn the Dutch with the civics that they embraced in 1360, so why would we rewind the clock on America?
As for the specific cases of the USSR, France (and Turkey; Atatürk deserves his due), Britain, and Indonesia see below:
USSR: state-sanctioned atheism as a requirement to hold public office is arguable closer to its own religion than secularism since it actually introduces a religious requirement as a condition of holding political office.
French Laïcité / Turkish Laiklik (Atatürk!): This is one brand of secularism, it isn't close to the most prominent globally. The French doesn't get to claim a monopoly on secularism anymore than Mormons can claim to be the only true Protestants.
Britain: This is the one very weird case where scholarly definitions break down. The Church of England is the official church of England---but only of England.
Indonesia: Modern Indonesia explicitly has no official state religion. Ipso facto the state-sanctioned faith cannot be considered "tolerant" of minority faiths since there is no state-sanctioned faith.
The
people may be more or less tolerant or religious in a country but how people feel is not civil policy.
I've attached a map of where there is an official state religion. It's colored based on religion.