You seem to claim that every "sensible person" wants God removed from the public square. No thanks.
"Thus, he manufactured a "heresy." This was his stock and trade, but the market wasn't anywhere near what it used to be. The American Revolution established there would be no room for the kind of monopoly Popes were used to. [It's no accident that there was only one Romanist signer of The Declaration of Independence; only two signed the Constitution.]"
The removal of God from the public life of a nation is an abomination, which has lead to where we are now. Pope Leo didn't "manufacture" this truth. The Americanist system is merely an umbrella that covered specific heresies that lead towards contempt for God in the public square, and which were beginning to assert themselves. And the reason only three Catholics signed the founding documents, is maybe, just possibly, related to the fact that Catholics comprised about 1% of the population at the time, and that Catholics were forbidden to practice law, (among other things), which meant very few Catholics were able to achieve the social and professional status that would befit the signer of said documents.
Maryland was established by Catholics, and with the Toleration Act of 1649 was the only colony to permit freedom of worship to all Christians. Protestants fleeing Anglican persecution in Virginia were granted land charters by the Catholic governor of Maryland...After establishing sufficient numbers, they overthrew the Catholic governor, burned nearly every Catholic Church in the colony, and outlawed Catholicism -- but at the same time levied a double taxation rate on Catholics.
Even in the wake of the American Revolution, some of the Framers (John Jay comes immediately to mind) still called for Catholics to be suppressed -- although I don't know of a any protest he made against the guns, money, and blood of ostensibly Catholic France that aided the United States during the Revolution.
It's really no surprise that the tiny, tiny number of Catholics in the colonies weren't involved in politics (although they gave disproportionate yeoman service to the Continental Navy). They'd have taken their lives into their hands.
It "seems" that way because you're under the mistaken belief that the Pope is God. No. He isn't. The correct removal of a meddlesome foreign churchman from America's governance doesn't equate to the removal of God. I demand the former, and abhor the latter.
That is what the Founders advocated, That is what I advocate, and that is what Leo XIII found to be a "heresy."
A good bit of the rest of what you write is nonsense. There was, for example, complete religious freedom in Pennsylvania. Catholics could not participate in the political life of the English colonies for the same reason that could not participate in England: the oaths required of them by the Crown were oaths they could not take. That was their choice.
The real truth is that adherents of the Church of Rome were not important in the Founding of America in any sense; and most importantly not in any ideological sense. The "Americanist Heresy" was established long before Leo XIII, because the "Americanist Heresy" was really the "heresy" of the Scottish Enlightenment, which the Roman Church could not abide.