This is another of those "Oh, please don't get me started" posts. I completely agree with everything you've said.
I'd like to preface this comment by saying almost without exception, the Americans I know - of all political and religious persuasions - are kind, funny, literate, sharp, intelligent people, who despair of the kind of lunacy you articulate in this piece. I believe a prosperous and peaceful America is in the interest of everyone, and I have immense love and admiration for many aspects of that great nation. Nor do I believe patriotism in and of itself is a bad thing. There is nothing wrong with Americans being proud of their country. Indeed, they still have much to be proud of.
All that said, something dark and terrifying has been stirred up in America.
It is interesting to me how religious American exceptionalists point to Israel as an example of God favouring one nation, but whilst the Jewish people do have a specific, unique destiny, due to God starting with them in the Old Testament (as you point out), it is lunacy to extrapolate America as God's Messianic force from Jewish rejection of Christ. Indeed, a simple reading of Romans 9, 10, and 11, and the very fact that Old Testament prophecies indicated Israel would become a nation again (as occured in 1948) makes clear that for all their faults (and there is much one can criticise Israel for on a political level) God is not done with Israel in any case.
It also begs the question, what was God doing in the intervening 1700 odd years before America was independent? Who was the Messiah at that point? Or did Jesus's death not come into effect until American Independence, kind of like a travel ticket only being valid on a certain date?
The unholy idolatry that has infiltrated the American church reminds me of Captain America: The Winter Soldier, where HYDRA infiltrates SHIELD to the point that SHIELD cannot be saved. It all has to go. Only then can we rebuild, hopefully based on the example of Jesus this time, for all mankind, not just America.