In response to @mccp77, noting of course the risk of this thread becoming a real 2000s style Christianity-Atheism style debate, I want to offer a rebuttal as I think earlier definitions of secularism and tolerance were more in line.
Using binary definitions of civics is a false path to go down. My preferred dictionary, Wiktionary, gives at least three pertinent definitions, "not specifically religious; lay or civil, as opposed to clerical" being the most relevant here. Your mistake is that you describe the civic as being about "religiosity is not a gov't policy", which is the real problem, as the religiosity civic describes the structure of religion, its role in society, and its relation to society, and not just the state. After all, deifiction, clergy and monasticism were rarely hard and fast rules. Medieval England was known for its vast, wealthy monasteries rich on wool exports, while also maintaining a highly structured clergy system. The Sumerian, Babylonian and Egyptian societies embodied paganism and the deification of a God-King, while also having advanced and organised clergy systems to enforce their beliefs, so on.
Again I would avoid literalism by looking at the other civics, most notably Conquest. "An act or instance of achieving victory through combat; the subjugation of an enemy" - well shouldn't the US have Conquest as its main civic for much of the 18th and 19th centuries then?
@Publicola is correct. While it's undeniable the Founding Fathers were motivated by deistic if not atheistic reasoning, they were all Christians who would fall under the banner of Protestantism in RFC DOC. If the social structure of that society whatever its form spits out an elite that is a single religion, then that Civilization in game has that religion as its State Religion. Tolerance then fits as either a policy of pragmatism, like as you said in (at least our popular conceptions of - I know many scholars (and also nationalists) of the Balkans and India that would greatly dispute this)) the Ottomans or Mughals, or arising out of debate and reason such as in the United States, or in the United Kingdom following Catholic Emancipation in 1829.
Where does secularism lie, then? I think we've touched on it above, with the USSR's State Atheism, French Lacite, Ataturk's reforms being the prime examples. The state here takes active role to exclude religion from civil society. It does not Tolerate it - it Secularises against it. Should the US and UK fit this definition? Murky waters. I'm from the UK and frankly I think most Brits would be uncomfortable describing our state and society as totally secular, faith schools are prominent throughout society, the House of Lords includes the Lords Spiritual, the King is the embodiment of the church. The US lies far closer to a secular society today, but that's not true in memory. As mentioned above many states embodied faith in their constitution, the Federal Government considered recognising the rights of the Mormons to Deseret, candidates and judges swear on bibles, and numerous Presidential candidates as recent as Ronald Reagan were brought to power promising stringent adherents to values of faith. If the US is to be secular ingame, it's much more appropriate under when the Warren Court repeatedly established secular principles in its rulings, and the failure of the American right to overturn those in the 1990s.
Lastly, I think that map is deeply erroneous in its implications. Russia today has an incestuous relationship between Presidency and the Moscow Patriarchate which has intimately endorsed the Putin regime and invasion of Ukraine - Russia is an Orthodox State. India demolishes Muslim mosques and protects the rights of cows - India is a Hindu state. Indonesia and Malaysia introduce laws regulating behaviour on the basis of Islamic values - they are Muslim states. To summarise: it is not solely the relationship between religion and the state, but religion and society that the religion civic should represent. I'll say no more to not get into a flame war.
Using binary definitions of civics is a false path to go down. My preferred dictionary, Wiktionary, gives at least three pertinent definitions, "not specifically religious; lay or civil, as opposed to clerical" being the most relevant here. Your mistake is that you describe the civic as being about "religiosity is not a gov't policy", which is the real problem, as the religiosity civic describes the structure of religion, its role in society, and its relation to society, and not just the state. After all, deifiction, clergy and monasticism were rarely hard and fast rules. Medieval England was known for its vast, wealthy monasteries rich on wool exports, while also maintaining a highly structured clergy system. The Sumerian, Babylonian and Egyptian societies embodied paganism and the deification of a God-King, while also having advanced and organised clergy systems to enforce their beliefs, so on.
Again I would avoid literalism by looking at the other civics, most notably Conquest. "An act or instance of achieving victory through combat; the subjugation of an enemy" - well shouldn't the US have Conquest as its main civic for much of the 18th and 19th centuries then?
@Publicola is correct. While it's undeniable the Founding Fathers were motivated by deistic if not atheistic reasoning, they were all Christians who would fall under the banner of Protestantism in RFC DOC. If the social structure of that society whatever its form spits out an elite that is a single religion, then that Civilization in game has that religion as its State Religion. Tolerance then fits as either a policy of pragmatism, like as you said in (at least our popular conceptions of - I know many scholars (and also nationalists) of the Balkans and India that would greatly dispute this)) the Ottomans or Mughals, or arising out of debate and reason such as in the United States, or in the United Kingdom following Catholic Emancipation in 1829.
Where does secularism lie, then? I think we've touched on it above, with the USSR's State Atheism, French Lacite, Ataturk's reforms being the prime examples. The state here takes active role to exclude religion from civil society. It does not Tolerate it - it Secularises against it. Should the US and UK fit this definition? Murky waters. I'm from the UK and frankly I think most Brits would be uncomfortable describing our state and society as totally secular, faith schools are prominent throughout society, the House of Lords includes the Lords Spiritual, the King is the embodiment of the church. The US lies far closer to a secular society today, but that's not true in memory. As mentioned above many states embodied faith in their constitution, the Federal Government considered recognising the rights of the Mormons to Deseret, candidates and judges swear on bibles, and numerous Presidential candidates as recent as Ronald Reagan were brought to power promising stringent adherents to values of faith. If the US is to be secular ingame, it's much more appropriate under when the Warren Court repeatedly established secular principles in its rulings, and the failure of the American right to overturn those in the 1990s.
Lastly, I think that map is deeply erroneous in its implications. Russia today has an incestuous relationship between Presidency and the Moscow Patriarchate which has intimately endorsed the Putin regime and invasion of Ukraine - Russia is an Orthodox State. India demolishes Muslim mosques and protects the rights of cows - India is a Hindu state. Indonesia and Malaysia introduce laws regulating behaviour on the basis of Islamic values - they are Muslim states. To summarise: it is not solely the relationship between religion and the state, but religion and society that the religion civic should represent. I'll say no more to not get into a flame war.
) Wiktionary readers everywhere stand in the posters above's debt. 
