Am I the only person in the world that doesn't understand patriotism?

When I talk to people about wars, bombings, death, and destruction, and the hand the United States has sometimes played in… not helping in the slightest and sometimes making things worse, I always get the following line, “Why don’t you stick with your own country?” Now, I understand the concept of family loyalty, but not patriotism. Sure, these are the people I share land with and a governing system with. They aren’t the only people in the world that are worth my time and worry. My government is extremely fallible, just like any other. We’re not better than anyone else just because we call ourselves Americans. The only thing that makes us different is the fact that our Founders had some pretty good ideas when it came to a legislative system. I like the way my country runs. I just don’t think that living within it’s boundaries makes me a demigod.

Can anyone explain to me why everyone seems to cling to the idea of there being a “them” and an “us”?