My argument is that "establishment of religion" meant something very different in 1787 than it does today. The only purpose of that clause is to prohibit a State Church. It was not designed nor intended to strip away pervasive Christian culture from our Government.
I will point out that several states had official state religions before during and after the Constitution was created. I think it wasn't until 1832 that the last state officially disbanded their state religion.
The establishment clause was created to avoid conflict between the individual states regarding religion. That the entire nation and government would be Christian was simply a given in that culture. Their use of the term "religion" in this context would be more accurately addressed by the use of the word "denomination" in it's place.
The US Constitution itself mentions Jesus Christ. Hard to disconnect Government from Christianity through a document that explicitly invokes Christ.
I think you have the history right.
I also don’t mind saying Christianity is the great hope of humanity.
It’s sad more people aren’t willing to publicly defend it.