You can't be patriotic because our history isn't perfect.
You can't be religious because it might offend someone.
God and country have been the common denominators of our culture and they are no longer seen as relevant, and there is nothing else to replace them. It seems like we are more interested in finding and emphasizing all the ways we are different from each other rather than rallying around anything we might have in common.
This is untrue; very few people have a problem with patriotism. Lots of people have a problem with various forms of nationalism, but none of that is about imperfection of history except insofar as certain breeds of nationalism center around glorifying and recreating bad aspects of history.
> You can't be religious because it might offend someone.
While this has always been true to an extent for faiths other than than that of the most dominant local form of Christianity, it is less true (not more) now than in the past.
Look, I come from the left. Growing up, there was definitely the sense that it is in poor taste to express enthusiasm about America or being an American. That it was something reserved for red necks who drive pick up trucks. The American flag, as a symbol, was considered gauche and the only time you would wear anything with the flag on it is if you were being self-consciously ironic. There was no sense that America was great. Instead, the focus was almost exclusively on America's flaws.
Or perhaps another way to think of it: if you had a friend who, every time a certain person came up, immediately started to enumerate that person’s flaws, what would you conclude about their feelings toward that person?
I definitely see that Christianity is getting less-and-less relevant in the US (as it has been in most other Western nations), but it seems like patriotism is its replacement, the Constitution is the new Bible and the founding fathers are the new apostles.