Why Did America Adopt Judeo-Christian Values as a Civil Religion in the 1940's?
Introducing a quasi-religious political correctness during the WWII Jewish holocaust years is probably no coincidence.
When was the Constitution amended to promote America as a Theocracy?
Why is the notion that 'America was founded on Judeo-Christian values' no longer acceptable to many Americans today?
Because it never was true. It is an often repeated lie told by the American Taliban to their ignorant flock who know no better. I'll admit, it is hard to tell which ones are lying about it intentionally, and which just don't know any better.
America was founded on Enlightenment values (Age of Enlightenment). In fact, to the best of my knowledge the USA is the first country to intentionally separate the power of the state from religious authority, allowing religion to continue as a personal matter between each person and whatever god or religion they believe in.
Thomas Jefferson and Ben Franklin seemed outright anti-theistic in some of their writings, with Jefferson often referring to superstitious beliefs and behaviors as "monkish," as in practiced by monks. Hell, Jefferson cut up four different Bibles to make the Jefferson Bible. Basically, Jefferson cut out all the obvious superstitious, supernatural BS from the Bible, and kept only the bits he thought useful. That also makes it a much shorter, easier, more enjoyable read
Myth of the Judeo-Christian Tradition and Other Dissenting Essays
Christian Theologian's View: "Today, people are tested by a new shibboleth, the 'Judeo-Christian tradition,'and though the tar pots and bushels of feathers are only figurative, haplessness is still in." M.Marty We, all the children of Abraham; who believe in the God of Israel; and trust the biblical script is vital for our society, but still have trouble with Judeo-Christian traditions both in the historical and especially in the theological sense.
https://www.amazon.com/Myth-Judeo-Christian-Tradition-Other-Dissenting/dp/B000STCEUW/ref=sr_1_11?s=books&ie=UTF8&qid=1549529960&sr=1-11&keywords=judeo-christian
Our society being based on "Judeo-Christian" morality is a JOKE (Reddit)
https://www.reddit.com/r/atheism/comments/9o20y3/our_society_being_based_on_judeochristian/
Judeo-Christian - History of the Term
Judeo-Christian is a term that groups Judaism and Christianity, either in reference to Christianity's derivation from Judaism, both religions' common use of the Torah, or due to perceived parallels or commonalities shared values between those two religions, which has contained as part of Western culture.
The term became prevalent towards the middle of the 20th century in the United States to link broader principles of Judeo-Christian ethics such as the dignity of human life, adherence to the Abrahamic covenant, common decency, and support of traditional family values.[1]
The concept of "Judeo-Christian values" in an ethical (rather than theological or liturgical) sense was used by George Orwell in 1939, with the phrase "the Judaeo-Christian scheme of morals."[2] It has become part of the American civil religion since the 1940s.
https://en.wikipedia.org/wiki/Judeo-Christian#History_of_the_term
History of Judeo-Christian
The term is used, as "Judæo Christian", at least as far back as in a letter from Alexander M'Caul dated October 17, 1821.[4] The term in this case referred to Jewish converts to Christianity.[5] The term is used similarly by Joseph Wolff in 1829, referring to a style of church that would keep with some Jewish traditions in order to convert Jews.[6]
https://en.wikipedia.org/wiki/Judeo-Christian#History_of_the_term
American Civil Religion
American civil religion is a sociological theory that a nonsectarian quasi-religious faith exists within the United States with sacred symbols drawn from national history. Scholars have portrayed it as a cohesive force, a common set of values that foster social and cultural integration. The very heavy emphasis on nondenominational religious themes is quite distinctively American and the theory is designed to explain this. The concept goes back to the 19th century, but in current form, the theory was developed by sociologist Robert Bellah in 1967 in his article, "Civil Religion in America".
https://en.wikipedia.org/wiki/American_civil_religion
Abrahamic Covenant
https://en.wikipedia.org/wiki/Covenant_(biblical)#Abrahamic_covenant
What does 'Judeo-Christian' mean? (Jewish World Review - 2004)
http://www.jewishworldreview.com/0304/prager_2004_03_30_04.php3