So despite being born and bred in America, atheists should not be considered Americans because they're not Christian? What about Jews, Muslims, Hindus, etc.? Does the First Amendment mean anything to you? And you call yourself an American.
I am proud to be an American, but that does not mean that I think America is the best country in the world. I think that no country in the world can have a monopoly on greatness. Every country has something to offer, no matter how small or seemingly trivial, and has potential, even if it's poor and/or backward. I'm glad that I'm living in America, but it's not because I think that Europe is a terrible place, quite the contrary. I've visited a few European countries and I would love to visit more, but I wouldn't want to live in Europe because America is my home, not because I think Europe is inferior.
And as an American, I know that the U.S. is not a Christian country and never was. And even if the opposite were true, we would not be the only Christian nation because there are many Christian countries in the world, some of which are not as economically prosperous as the United States.
One does not have to be a Christian to be a "real" American. One has to abide by the laws of the land, feel free to protest if they are unjust, and in some way, contribute to universal peace, equality, justice, and freedom, which are the ideals that most Americans cherish deeply and which people of any religion or lack thereof can do. And contrary to what this person believes, these are not that different from what Europeans believe in, and have believed in and worked for.
If living in a multicultural, open, relatively free society does not suit you, Annie, perhaps you should try living in Saudi Arabia or any of the other repressive theocracies which do not have the freedoms that we often take for granted and see how much freedom you get there.