The prohibition of "Establishment" of religion absolutely was understood by EVERYONE of that era as meaning all forms of Protestant Christianity were to be treated equally and none favored by any government.
In practice this meant that that the majority religion in a town could collect TAXES to support the local denominational church even from members of another denomination (unless the local member of a minority denomination had a certificate of his belonging and attending another denomination's church).
In practice it also meant that Catholicism, Judaism and Quakerism were LEGALLY substandard to basic vanilla Protestantism.
Anti-Catholicism (actually pro-generic-Protestantism) was very much a part of the USA's founding.
While I am glad that anti-Catholicism is no longer legal, I regret that the COnstitution has been ignored in doing so. Inother words, I am not willing to accept the good outcome at the expense of destroying the Constitution.
The USA has always overtly and officially relied upon God. Those who declare otherwise are truly very ignorant - though understandably so given the Supreme Court's pretense over the last 140 years that increasingly ignores the facts.
Those truly interested in the facts can freepmail me for the references.