> ... over the past ten years or so we have seen the establishment of an entirely new set of sacred social norms ...
That depends on who you are, and where you hang out.
By "sacred social norms", I presume that you mean what some call the "social justice movement": liberal perspectives on "race", culture, sexuality, gender, and other human rights. It's true that those norms now apply for liberal mass media, academica, and large enterprises. And increasingly, they've become part of state and federal law.
Those norms reflect activism over at least the past 200 years. However, change hasn't been steady or even monotonic. Recent reverses occurred during the Reagan era, driven by the Moral Majority. And again during the Bush II era, driven by them and the New Right.
American society has also become increasingly polarized since the 60s. Although the mass media has become increasingly liberal, the Fox News Network and associated talk radio developed. And since the early 90s, development of the Internet has dramatically increased polarization.
So now we're in the Trump era. By 2016, American society was already so polarized that the liberal mass media was totally blind sided by Trump's election. And even after three years, they're still convinced that it was a Russian plot.
Anyway, it's hard to say whether the intolerance of the "social justice movement" has caused the backlash, or whether the backlash has driven the intolerance. But either way, both sides are ~equally intolerant.
And yes, it's a disturbing development. At some point, it may drive the US to partition. Much like India split off Pakistan, but on a larger scale.